A Technical Issues Paper prepared for the
Federal Office of Rural Health Policy
Health Resources and Services Administration
US DHHS
Thomas C. Ricketts, Ph.D.
Karen D. Johnson-Webb, M.A.
Patricia Taylor, Ph.D.
June 1, 1998
Definitions of Rural:
A Handbook for Health Policy Makers and Researchers
Prepared under Contract Number HRSA 93-857(P)
From the Federal Office of Rural Health Policy
to the North Carolina Rural Health Research Program
Cecil G. Sheps Center for Health Services Research
University of North Carolina at Chapel Hill
June 1998
Introduction
“…the perceived magnitude of rural health care problems and the impact of any change
in public policy depend on how ‘rural’ is defined.”—Maria Hewitt (1992)
In developing policies to address problems of access and health status for rural people in the
United States, policy makers must specify the definition of “rural.” At the national level, there are
two major ways to define rural: the Office of Management and Budget metropolitan-nonmetropolitan
classification of counties and the US Bureau of the Census classification of areas
and population.
Neither of these two principal, nationally-applicable definitions completely and adequately
captures the essence of what is rural nor provides a universally-applicable method that precisely
separates urban from rural populations or places.
This handbook was commissioned by the Federal Office of Rural Health Policy as part of its
continuing efforts to support policy-relevant rural health services research and analysis. It
describes these two major methods of describing rurality, the OMB and Census methods, and
major variations of those methods. The report is meant to assist policy makers in identifying
classification methods they can use to target programs and policies to rural problems and to guide
policy analysts in understanding how to delineate urban and rural populations and areas.
“Until the population is uniformly defined, it is very difficult to address…problems in an
unambiguous manner from secondary data sources”—Vernon Briggs, Jr. (1981)
1
Executive Summary
Policy makers are often required to define what is “rural”
or “urban” in order to apply national policies. There are two
principal definitions of rural used by the federal government:
the Office of Management and Budget’s (OMB) “Metropolitan-
Nonmetropolitan” system and the Bureau of the Census’
“Urban-Rural” classification of populations.
The Bureau of the Census defines urban as comprising all
territory, population, and housing units located in urbanized
areas (UAS) and in places of 2,500 of more inhabitants outside
of UAs. Territory, population and housing units that the census
Bureau does not classify as urban are classified as rural. In the
1990 Census, 24.8% of the national population was classified
as rural. The rural proportion has decreased since 1870 even
while the total number of people classified as rural has
increased along with the increase of the nation’s population.
Metropolitan and nonmetropolitan areas are defined on the
basis of counties by the OMB. Metropolitan areas contain (1)
core counties with one or more central cities of at least 50,000
residents or with a Census Bureau-defined urbanized area and
a total metro area population of 100,000 or more and (2)
fringe counties that are economically tied to the core counties.
Nonmetropolitan counties are outside the boundaries of metro
areas and have no cities with as many as 50,000 residents. In
1996, 2,522 of 3,139 counties or county-equivalents were
classified as nonmetropolitan. These counties included
52,393,300 persons or 19.8% of the total 1996 national
population estimate of 264,100,960.
Rural and urban areas and populations identified by the
OMB and Census systems have substantial disparities. In 1990,
37.3% of nonmetropolitan people lived in urban areas and
13.8% of metropolitan people were classified as rural. This
incomplete overlap represents one of several problems in
accurately describing rural and urban populations using these
two, dichotomous systems of classification.
Agencies and Offices in the Federal Government have
created variations of these systems in order to more accurately
target programs and projects. These include the application of
the Census Bureau “Urbanized Area” definition as part of the
criteria for designation of Rural Health Clinics under P.L. 95-
210 and amendments. A modification of the OMB system
developed by Goldsmith is used in the eligibility standards for
application of the Universal Service Provisions of the
Telecommunications Act of 1996 (P.L. 104-104). The US
Agency on Aging has created a ZIP-code-based system of
identifying rural and urban areas to apply provisions of the
1992 Amendments to the Older American Act.
The OMB and Census methods are most often used in
policy analysis and research and there are delineations within
the OMB system which are used to classify counties according
to their relative “urbanicity” or “rurality.” These include the
Urban Influence or Urbanicity Codes, and the Rural-Urban
Continuum Codes developed by the US Department of
Agriculture. The USDA also classifies nonmetropolitan counties
on the basis of their primary economic activity. The Economic
Research Service (ERS) of the USDA is working with the
Federal Office of Rural Health Policy to create a hybrid of the
OMB and Census systems using census tracts as the basic unit
of designation.
There are a significant number of counties and areas in the
United States which are very sparsely populated and which
have unique problems in health service delivery and access
related to this settlement pattern. Places with 6 or fewer
persons per square mile are considered “frontier” counties or
communities and 383 counties (excluding Alaska boroughs)
met this criterion in 1995.
The identification of areas as “urban,” “rural,” or “frontier”
continues to be a problem for policy makers. There is clear
evidence that the characteristics that distinguish rural and
frontier places from urban communities have important effects
on health service delivery and access. New data analysis
methods and improvements to geographic information systems
(GIS) are making it possible to more carefully and accurately
identify the range of rural and urban places.
2
Federal Definitions of Rurality
The federal government has been involved in the
classification of areas and populations into rural and urban
categories since the beginnings of the Republic; these
classifications were designed for statistical purposes and to
target programs and funds. The current classifications of urban
and rural places and people on a national basis date back to
the first decade of this century. In general, “rural” is a term
used by the Census Bureau to classify people who live in places
with small populations or unincorporated areas with
population density less than 1,000 per square mile. Non-metropolitan
is
used by the US
Office of
Management and
Budget (OMB) and
refers to counties
that do not meet
minimum
population
requirements, do
not have a central
city or do not
relate closely to
larger urban
places. The OMB
classification deals
with counties, governmental jurisdictions which have
traditionally been used to report health as well as population
data. Since most national health data are reported at the county
level it is often easier to classify many populations or groups on
the basis of the metropolitan designation.
Other agencies have created definitions for their own
programs but those definitions usually depend upon a
combination of the OMB and Census criteria. For example, the
rules guiding federal grants for solid waste disposal projects for
rural communities specify that those grants
can be made to “municipalities with a
population of five thousand or less, or
counties with a population of ten thousand or
less, or less than twenty persons per square
mile and not within a metropolitan area (42
U.S.C. Ch. 82 Sec. IV § 6949).
The Census Bureau and
Definitions of Urban and Rural
Rural was first used by the Census
Bureau in 1874 when it was defined as the
population of a county living outside cities
or towns with 8,000 or more inhabitants
(Whittaker, 1982). That population
threshold was changed to 2,500 in 1910.
The Census Bureau now defines "urban" as
comprising all territory, population, and
housing units in urbanized areas and in places of 2,500 or
more persons outside urbanized areas. The terms urban,
urbanized area, and rural are specifically defined by the
Census Bureau. Other federal agencies, State agencies, local
officials, and private groups may use these same terms to
identify areas based on different criteria.
An urbanized area (UA) is defined as a continuously built-up
area with a population of 50,000 or more. UAs comprise
one or more central places and the adjacent densely settled
surrounding area, with a population density generally exceeding
1,000 inhabitants per square mile. There are urban places
outside of UAs which are any incorporated place or Census
Designated Place (CDP) with at least 2,500 inhabitants. A CDP
is a densely settled population center that has a name and a
community identity and is not part of any incorporated place.
All territories, populations, and housing units that the
Census Bureau does not classify as urban are classified as rural
(Bureau of the Census, 1994). For instance, a rural place is any
incorporated place or CDP with fewer than 2,500 inhabitants
that is located outside of a UA. A place is either entirely urban
or entirely rural, except when designated as an extended city.
An extended city is an incorporated place that contains large
expanses of sparsely populated territory for which the Census
Bureau provides separate urban and rural population counts.
Territory outside of urbanized areas and urban places is
designated rural, and can have population densities as high as
999 per square mile and as low as 1 or 2 per square mile.
The rural population is currently divided into farm and
non-farm classifications and populations were enumerated in
3
• There are two principal
definitions of rurality used for
federal health care policy
• The Census Bureau bases its
definition on a combination
of population density,
relationship to cities, and
population size
• The Office of Management and
Budget (OMB) classifies
counties on the basis of their
population size and integration
with large cities
All territories, populations, and housing
units that the Census Bureau does not
classify as urban are classified as rural
Rural Population, in Millions
Rural Population
Percent Rural
Year
Percent Rural Population
Total Rural Population and Proportion
Population Classified as Rural, 1850-1990
these categories by the census as early as 1860. Farm
population, under current census definitions, includes people
living in rural areas on properties of one acre of land or more
where $1,000 or more of agricultural products were sold (or
would have been sold) in the past 12 months. In 1860, the
farm population was 48.1 percent of the total, and in 1920, 30
percent. In the 1990 census the rural-farm population was 1.9
percent of the total population; in 1996, the Census Bureau
announced plans to curtail reporting of this classification.
Map 1 displays the proportion of each state’s population
classified as rural by the 1990 census and Table 5, the
number and proportion of people classified as rural by the
census by state. In the table it is possible to see that the
“most rural” states according to the numbers of rural
people, are Pennsylvania, Texas, and North Carolina.
According to proportion of population classified as rural,
Vermont, West Virginia and Maine are the top three. The
table reveals some unexpected variations; for example,
Delaware has more rural people than Nevada or Wyoming
and New Jersey has more rural people than North and
South Dakota combined.
The US Census Bureau describes its definitions of
“urban” and “rural” in the document, 1990 Census of
Population and Housing, “Population and Housing Unit
Counts,” (CPH-2-1.) and a description is included on
their World Wide Web Page at http://www.census.
gov:80/population/censusdata/urdef.txt. Detailed
criteria for the designation of Urbanized Areas can
be obtained from the Chief, Geography Division,
U.S. Bureau of the Census, Washington, DC 20233. A
complete guide to Census Geography is available in
the “Geographic Areas Reference Manual” issued in
November, 1994 by the Economics and Statistics
Administration, Bureau of the Census
US Office of Management
and Budget Metropolitan-
Nonmetropolitan System
The US Office of Management and Budget
defines Metropolitan Areas (MA) according to
published standards that are applied to Census
Bureau data. Map 2 highlights the counties in
the United States not classified as metropolitan
as of June 1997. Alaska, Hawaii, and the six
New England states have slightly different
treatment. Alaska is classified into boroughs and
one county, Anchorage, is classified as
metropolitan, due to its urban nature. The
boroughs are easily considered county-equivalents,
and all of Alaska except Anchorage is considered
rural by most federal health programs. The major islands of
Hawaii are county equivalent units and Oahu is classified as
metropolitan with the other islands classed as nonmetropolitan.
The New England states’ metropolitan areas are classified as
New England county metropolitan areas (NECMAs) and are
defined in terms of cities and towns but generally follow
county boundaries.
The general concept of a metropolitan area is that of a
core area containing a large population nucleus, together
with adjacent counties having a high degree of economic
and social integration with that core. Currently defined MAs
are based on the application of 1990 standards to 1990
decennial census data (Federal Register on March 30, 1990).
These definitions were announced by OMB effective June
30, 1993. The designation of counties as metropolitan or
nonmetropolitan is a continuous process and is not
dependent on changes in the definition of metropolitan.
Standard definitions of metropolitan areas were first issued
in 1949 by the Bureau of the Budget, the predecessor of OMB,
4
URBANIZED AREAS (UAs)
• The Census Bureau delineates urbanized areas (UAs) to provide
a better separation of urban and rural territory, population, and
housing in the vicinity of large places.
• A UA comprises one or more places ("central place") and the
adjacent densely settled surrounding territory ("urban fringe")
that together have a minimum of 50,000 persons.
• The urban fringe generally consists of contiguous territory
having a density of at least 1,000 persons per square mile. The
urban fringe also includes outlying territory of such density if it is
connected to the core of the contiguous area by road and is
within 1 1/2 road miles of that core, or within 5 road miles of the
core but separated by water or other undevelopable territory.
County A
County B
County C
County D
County E
Metropolitan Area (MA)
Nonmetro Counties
Central City
Urbanized
areas
Urban Places
Urban Places
Rural Area Rural Area
under the designation,
“standard metropolitan
area” (SMA). The term
was changed to
“standard metropolitan
statistical area” (SMSA)
in 1959, and to
“metropolitan
statistical area” (MSA)
in 1983. The current
collective term
“metropolitan area”
(MA) became effective
in 1990. OMB has
been responsible for
the official metropolitan areas since they were first defined,
except for the period 1977 to 1981 when they were the
responsibility of the Office of Federal Statistical Policy and
Standards in the US Department of Commerce. The standards
for defining metropolitan areas were modified in 1958, 1971,
1975, 1980, 1990, and 1993.
The current OMB standards generally provide that each
MA must include at least:
(a) One city with 50,000 or more inhabitants, or
(b) A Census Bureau-defined urbanized area (of at least
50,000 inhabitants) and a total metropolitan population of
at least 100,000 (75,000 in New England).
Under these standards, the county (or counties) that contains
the largest city becomes the central county (or counties if the
city covers more than one county) of a MA. Any adjacent
counties that have at least fifty percent of their population in
the urbanized area surrounding the largest city are also
included in the MA. Additional "outlying counties" are
included in the MA if a substantial proportion of the employed
people in the county commute to the central place. There are
other characteristics which are considered, including
population density and percent urban.
Changes in the designation of MAs since the 1950 census
have consisted chiefly of (1) the recognition of new MAs as
core areas reached the minimum required city or area
population; and (2) the addition of counties or New
England cities and towns to existing MAs as new census
data showed them to qualify. Also, some formerly
separate MAs have been merged with other areas, and
occasionally territory has been transferred from one MA
to another or from an MA to nonmetropolitan territory.
Map 3 depicts the counties that have changed status from
nonmetropolitan to metropolitan since 1983; 118
counties have been redesignated between June 30, 1983
and June 30, 1995.
Most changes in metropolitan designations have
taken place on the basis of analysis of decennial census
data. There are policies for making changes between
censuses and updates can occur at any time. Because of these
changes in standards, users must be cautious in comparing
metropolitan and nonmetropolitan area data for different
years. For some purposes, comparisons of data for MAs as
defined at given dates may be appropriate, for example when
describing changes in the “nonmetropolitan” population over
time, using the counties designated in 1970 and 1990 would
be acceptable. However, to compare a change in a stable set of
counties, the set of designated counties for one year would use
data from multiple years for comparisons. In 1997,
nonmetropolitan counties made up 73 percent of all counties,
or 2,250 out of 3,081 counties or county-equivalent units.
MSAs are used by federal agencies for collecting,
analyzing, and publishing data and for implementing programs
and resource allocation (though the criteria are not specifically
designed for this). One example is the use of MA status for the
categorization of hospitals as either rural or urban for purposes
of Medicare reimbursement. The business community utilizes
MAs in investment decisions and market feasibility studies; the
data, however, are not intended for this use and OMB will not
alter them, nor provide support for non-statistical uses.
The Office of Management and Budget publishes
bulletins describing their decisions and actions. The most
current description of Metropolitan Area definitions is
included in METROPOLITAN AREAS 1995 LISTS I-IV, Statistical
Policy Office, Office of Management and Budget,
Attachments to OMB Bulletin No. 95-04. That Bulletin is
available on the World Wide Web at http://www.
whitehouse.gov/WH/EOP/OMB/html/bulletins/95-
04attachintro.html. Documentation can be obtained from
the Statistical Policy Office of the Office of Information and
Regulatory Affairs of the OMB. Inquiries can be directed to
Maria E. Gonzales, (202) 395-7313
OMB’s, Metro-Nonmetro and Census’,
Urban-Rural Definitions: Strengths and
Weaknesses
The fact that there are two primary federal definitions that
identify “rurality” in the United States creates occasional
confusion and some degree of controversy. The confusion
5
• The number of
nonmetropolitan counties
changes from year to year
• Since 1983, 117 counties
have been redesignated
metropolitan
• Not all redesignations are
from nonmetro to metro,
occasionally a metro county
will “revert” to nonmetro
status
Rural 14%
Urban 86% Rural 62%
Urban 37%
Overlap of OMB and Census
Definitions of Populations
Metropolitan Nonmetropolitan
stems from the fact that the two definitions do not completely
overlap; they apply to different geographies and they were
created for different reasons. Metropolitan counties are not
synonymous with wholly urban counties but can contain
significant rural populations (as defined by the Census).
Nonmetropolitan counties have significant urban
populations. Table 1 examines the counties designated
metropolitan and nonmetropolitan as of 1994 and shows
how the 1990 Census Bureau population classifications of
urban and rural were distributed across them. The upper-left
cell in the table shows that 13.8 percent of the population in
metropolitan counties were classified as rural by the Census
and these 26.5 million people made up 43% of the total US
rural population.
Applying either of the two systems to populations or areas
creates some degree of inaccuracy since neither system
perfectly agrees with the common understanding of rural and
urban. Metropolitan counties may include substantial rural
areas, as are found in the larger, western counties, especially in
California and Arizona. Likewise, an MSA may not include
significant suburban populations closely integrated with cities
in adjacent counties. The Census Bureau’s urban population
includes many people living in towns with less than 10,000
residents and its rural population includes significant numbers
living close to named places in areas where the population
density can be as high as 999 people per square mile. It is clear
that neither method is perfect for the depiction of a “rural”
population where rural means persons in lower density or
smaller settlements who are at some distance from urban
places. This fact has been recognized by several analysts (Jonas
& Wilson, 1997; Goldsmith, Puskin & Stiles, 1992) and by
demographers and geographers who have proposed alternative
systems (Ghelfi & Parker, 1995; Pickard, 1988; Cromartie &
Swanson, 1995).
The problems that accompany the application of the
Census or the OMB definitions or a combination of the two
to a policy-related program for the allocation of resources or
the identification of need have
recently been highlighted by the
application of the Universal
Service provisions of the Federal
Telecommunications Act of
1996. Regulations implemented
subsequent to the Act
recognized the imprecision of
the Census Bureau and OMB
systems and called for a hybrid,
the Goldsmith variant, which
attempts to deal with the
problem of substantial rural
areas included in MSA counties.
The specifics of the Goldsmith
system are described in the next
section along with other
variations of the federal
designation systems.
Variants of Principal
Federal Definitions Used
in Federal Policy
Non-Urbanized Areas—The Definition of
Geographic Eligibility for the Rural Health
Clinic Program
The problem of appropriately identifying rural areas was
recognized in the legislation creating Rural Health Clinics
(RHCs). In December, 1977, Congress passed Public Law 95-
210, the Rural Health Clinic Services Act, to redress problems
with reimbursement of nurse practitioners and physician
assistants (nurse midwives were later added in rural clinics)
and increase the availability and accessibility of primary care
services for residents of rural communities. It was apparent
that both the OMB and Census definitions excluded certain
areas which were clearly rural in nature but did not fall under
existing definitions of “rural” or “nonmetropolitan.” These areas
were most often located in the western states where counties
covered immense expanses of geography and included sparsely
populated areas. The solution was to use the Census Bureau
definition of “Urbanized Area” (which is described above) as
the factor for excluding sites for Rural Health Clinic designation.
Clinics located outside of “Urbanized Areas” are geographically
eligible for RHC designation.
Large Metropolitan Counties and
Rural Populations. (The Goldsmith
Modification)
Residents of metropolitan counties are generally thought to
have easy access to the relatively concentrated health services
of the county’s central areas. However, some metropolitan
6
Table 1. Rural, Urban, Metro and Nonmetropolitan
Population of the U.S., 1990
Census OMB Metropolitan OMB Nonmetropolitan Total
Rural 26,525,155 35,133,175 61,658,33
13.8% of Metro 62.7% of Nonmetro (24.8% of total)
43% of Rural 57% of Rural
Urban 166,201,175 20,850,368 187,051,543
86.2% of Metro 37.3% of Nonmetro (63.2% of total)
88.8% of Urban 11.2% of Urban
Total 192,726,330* 55,983,543* 248,709,873
(77.5% of total) (22.5% of total) 100%
*1996 US Census estimates show a reduction of the population in nonmetropolitan areas to
52,393,313 or 19.83% of the total 1996 national population estimate of 264,100,960.
counties are so large that they contain small towns and rural,
sparsely populated areas that are isolated from these central
clusters and their corresponding health services by physical
barriers. Using 1980 census data, Harold Goldsmith, Dena
Puskin, and Dianne Stiles (1992) described a methodology to
identify small towns and rural areas within large metropolitan
counties (LMCs) that
were isolated from
central areas by
distance or other
physical features. The
process involves first
identifying the LMCs,
defined as
metropolitan counties
having at least 1,225
square miles. The next
step is to identify the
large (> 25,000
inhabitants) cities in
the county. The final
step is to identify the
rural census tracts in
those eligible counties that are without easy geographical access
to any large cities. The most important criterion used to
identify these isolated rural tracts is that comparatively few
persons in these tracts commuted to work in the cities and
their suburbs (less than 15 percent of the labor force).
An analysis of the application of the work by Goldsmith
and colleagues, using 1980 census data, revealed that just over
32 million people live in LMCs in the 20 states with at least
one such county, and that 6.2 percent of the population of
LMCs resided in isolated rural areas. This represents a 4
percent increase in the number of persons considered to reside
in rural areas. The state with the largest number of isolated
rural populations within LMCs was California, with nearly one
million such residents, and the state with the smallest number
was Wyoming, with about 3,000.
The “Goldsmith” variant was developed for the Federal
Office of Rural Health Policy’s Rural Health Outreach Grant
Program and is now also used in that Office’s Rural Network
Development and Telemedicine grant programs. It has been
adopted by the Federal Communications Commission as one
component of the definition of “rural” that is used to determine
the eligibility of public and private nonprofit health care
providers for a telecommunications rate subsidy as provided in
the Telecommunications Act of 1996, P.L. 104-104, in the
Universal Services Provision of the Act.
The Goldsmith Modification has been useful for expanding
the eligibility for federal programs that assist rural
populations—to include the isolated rural populations of large
metropolitan counties. However, its authors and the federal
agencies that use the modification recognize its limitations. The
principal one is that the criteria for identifying isolated rural
areas have been applied to only very large counties though it is
obvious there are equally isolated areas in many of the smaller
counties of the nation. Also, it has not been possible to
thoroughly update the designation of rural census tracts.
Goldsmith, et al., used 1980 census data in their original work
and the requisite special data base from the 1990 census has
not, to date, been compiled. If the Goldsmith Modification is
modified to be more accurate, then the urbanized areas of
nonmetropolitan counties should perhaps be considered for re-classification
out of the “rural” category.
US Administration on Aging
Definition of Rural
The U.S. Administration on Aging was required by the
1992 Amendments to the Older Americans Act to produce a
standard definition of rural. The Administration initially chose
to use the Census Bureau definition but, based on their
assessment that this was not practical to implement, created a
“modified census definition of rural” which reads as follows:
Rural—an area that is not urban. Urban areas comprise
(1) urbanized areas (a central place and its adjacent densely
settled territories with a combined minimum population of
50,000) and (2) and incorporated place or a census
designated place with 20,000 or more inhabitants.
To operationalize this definition required a compromise since
data were not collected at the levels identified in the definition.
The AoA chose to combine the identification of urbanized areas
as defined by the Census Bureau and ZIP code postal
boundaries to classify all ZIP code areas as either urban or
rural. There are two criteria for designation of a ZIP area as
urban: (1) if one percent or more of the ZIP area falls within an
urbanized area; and (2) if a ZIP area is affiliated with a place of
20,000 to 49,000 residents located outside an urbanized area.
All other ZIP areas are classified as rural. The designations
distributed by the AoA in the summer of 1996 were based on
1995 ZIP areas provided by a private vendor, Claritas
Corporation, and the AoA noted that these ZIP areas are likely
to change.
Copies of the “Guidebook for Operationalizing AoA’s
Definition of Rural” are available from the National
Resource and Policy Center on Rural Long-Term Care.
Contact Mercedes Bern-Klug at (913) 588-1266. E-mail:
MBERNKLU@KUMC.EDU
Classifications of Rurality
Within Federal Designations
Urban Influence Codes
The US Department of Agriculture has worked with
county-level data systems and developed several variants over
the years; the work of USDA demographers Calvin Beale and
Glenn Fuguitt cover many of these variations (Beale and
7
Additional criteria used in
the identification of the
LMCs isolated rural census
tracts are described in the
Goldsmith, Puskin, and
Stiles monograph,
“Improving the
Operational Definition of
‘Rural Areas’ for Federal
Programs,” available on
the Internet at
http://www.nal.usda.gov/
orhp/goldsmit.htm.
Johnson, 1995; Butler and Beale, 1994; Fuguitt, 1975). In
1980, the USDA circulated a classification scheme which
described nonmetropolitan counties according to their
“accessibility to metropolitan centers and small cities” (Deavers
and Brown, 1980).
The problem of inter-county relationships has been one
that has challenged analysts for some time. Responding to the
need to consider inter-county flow outside metropolitan areas,
Linda Ghelfi and Timothy Parker, of the Economic Research
Service in the USDA, proposed another set of codes, the
“Urban Influence” codes, to help categorize counties to reflect
their economic and social roles as opposed to their relative
population size and physical adjacency. This new system is
based on the theory that access to larger metropolitan
economies, such as centers of information, communication,
trade, and finance, provides an economic development
advantage for smaller nonmetropolitan economies (Ghelfi and
Parker, 1995). Table 2 summarizes the 9-level Urban Influence
coding systems.
The Urban Influence codes take into account two factors:
the county’s largest city and the county’s proximity to other
counties with large, urban populations. The codes divide the
3,141 counties and independent cities in the United States into
9 groups. Metropolitan counties are classified by the size of the
metropolitan area—populations of more than one million and
those with less. Nonmetropolitan counties are classified by
their adjacency to these metropolitan areas—adjacent to a large
metropolitan area, adjacent to a small metropolitan area, and
not adjacent to a metropolitan area. Within each of these
categories, nonmetropolitan counties are further classified by
the size of their own largest city.
The Urban Influence system accounts for the effect of
smaller, central cities in its structure. This would be important
in health policy due to the structure of health care systems
which involve threshold levels of institution size and
complexity of the medical community based on the population
of the largest city in a service area. Map 4 shows the 9-level
system created in 1993 using 1990 data.
The Urban Influence codes are available from the
Economic Research Service of the USDA at their Internet
site, http://www.econ.ag.gov/briefing/rural/data/urbinfl.txt.
For further information contact Linda Ghelfi, USDA,
Economic Research Service, 1800 M St., NW., Washington,
DC 20036-5831. Phone: (202) 219-0484 E-mail: lghelfi@
ECON.AG.GOV or Tim Parker at the same address, E-mail:
tparker@ECON.AG.GOV
Rural-Urban Continuum Codes for
Metropolitan and Nonmetropolitan Counties
The Rural-Urban Continuum Codes (RUCC) classify all US
counties into 10 categories. The classification scheme groups
metropolitan counties into four levels by size, and
nonmetropolitan counties into six categories by the size of the
urban population (number of people living in towns of 2,500
or more) and nearness to a metropolitan area. The codes were
originally developed in 1975, and were updated in 1983 and
slightly revised in 1988. They are sometimes called “Beale
Codes,” after Calvin Beale, who contributed to their
development. These codes allow researchers to break county
8
Table 2.
USDA Urban Influence Codes
Code Definition - Counties
(No “0” coding used in this system)
1 Large—Central and fringe counties
of metropolitan areas of 1 million
population or more
2 Small—Counties in metropolitan
areas of fewer than 1 million
population
3 Adjacent to a large metropolitan area
with a city of 10,000 or more
4 Adjacent to a large metropolitan area
without a city of at least 10,000
5 Adjacent to a small metropolitan area
with a city of 10,000 or more
6 Adjacent to a small metropolitan area
without a city of at least 10,000
7 Not adjacent to a metropolitan area
and with a city of 10,000 or more
8 Not adjacent to a metropolitan area
and with a city of 2,500 to 9,999
population
9 Not adjacent to a metropolitan area
and with no city or a city with a
population less than 2,500
Note: Adjacent counties are physically adjacent to one
or more MSAs and have at least 2 percent or more of
the employed labor force in the nonmetropolitan
county commuting to central metropolitan counties.
The metro-nonmetropolitan definition is based on
Office of Management and Budget definition as of
June 1, 1993.
data into sub-groups beyond the basic metropolitan–
nonmetropolitan classification. This is especially useful for the
analysis of factors or characteristics of nonmetropolitan areas
that are related to population density and metropolitan
influence. Table 3 describes the specific levels of the RUCC.
The nonmetropolitan levels are described by the USDA as
“Urbanized” (Codes 4 and 5), “Less Urbanized” (Codes 6 and
7), and “Thinly Populated” (Codes 8 and 9).
Metropolitan counties are further classified by the
population size of the entire MSA of which they are a part;
then counties in MSAs of one million or more are assigned a
code by whether they are central or more peripheral counties.
For those counties classified as nonmetropolitan, counties
adjacent to an MSA are identified. Adjacent counties 1) are
physically adjacent to one or more MSAs and 2) have at least
two percent of the employed labor force in the
nonmetropolitan county commuting to central metropolitan
counties. Finally, nonmetropolitan counties not meeting the
above criteria for adjacency are classified as “not adjacent.”
Map 5 depicts the counties by the Rural-Urban Continuum
Code designations as of 1994.
Rural-Urban Continuum Codes classifying all U.S.
counties are available on the Internet. The World Wide Web
site http://www.mannlib.cornell.edu/data-sets/rural/89021/
provides a full file. Questions concerning the file can be
directed to Margaret Butler, Economic Research Service,
1800 M St., NW., Washington, DC 20036-5831. Phone (202)
219-0534, E-mail Mbutler@ econ.ag.gov
A Comparison of the Urban Influence Codes
With The Rural-Urban Continuum Codes
While the Urban Influence Codes break metropolitan areas
only into large and small, the Rural Urban Continuum Codes
differentiate the larger counties into “central” and “fringe”
classifications. This can be of use when considering specific
issues of adjacency. However, analyses showed that there was
little difference in
population and economic
growth between
nonmetropolitan counties
adjacent to either the
central or the fringe
metropolitan counties.
Looking at the maps of
the RUCC (Map 5) and the
Urban Influence Codes
(Map 4), it is apparent that
the Urban Influence system
more effectively creates
regional areas that appear
to reflect the tendency of
economic systems to
“centralize” around very
large metropolitan counties.
The latter centralization follows the structure of health care
services, where very large, tertiary care health centers and
medical schools are located in the central, large metropolitan
counties and their influence on referral patterns is likely to be
stronger in adjacent versus non-adjacent counties. It also shows
the location of non-adjacent nonmetropolitan counties with
smaller cities (>10,000), where secondary care health centers
and specialists are likely to be located.
In Development: Sub-County Definitions of
Metropolitan and Nonmetropolitan areas
and the Rural-Urban Continuum Using
Census Tracts as the Basic Unit
The Economic Research Service (ERS) in the US
Department of Agriculture (USDA), and the Office of Rural
Health Policy, DHHS, are collaborating to develop a more
precise definition of populations along the urban-rural
continuum. This system will use the OMB criteria (with some
modifications) but apply them at the census tract level rather
than the whole county. John Cromartie, of the ERS, and
Richard Morrill, of the University of Washington, are the
geographers developing this system. The first publication on
their methodology and early results are expected in mid-1998.
The impetus for this project came from early work in the ERS
by Cromartie and Linda Swanson (1995) published in Rural
Development Perspectives.
USDA ERS Typology of Primary
Economic Activity
The ERS (1995) of the US Department of Agriculture
(USDA) developed a rural typology that provides a way to
identify groups of US nonmetropolitan counties sharing
important economic and policy traits. Through this typology,
the ERS provides a way to geographically identify groups of
9
Table 3. USDA, ERS Rural-Urban Continuum Codes
Code Metropolitan Counties:
0 Central counties of metropolitan areas of 1 million population or more
1 Fringe counties of metropolitan areas of 1 million population or more
2 Counties in metropolitan areas of 250,000 to 1 million population
3 Counties in metropolitan areas of fewer than 250,000 population
Code Nonmetropolitan Counties:
4 Urban population of 20,000 or more, adjacent to a metropolitan area
5 Urban population of 20,000 or more, not adjacent to a metropolitan area
6 Urban population of 2,500 to 19,999, adjacent to a metropolitan area
7 Urban population of 2,500 to 19,999, not adjacent to a metropolitan area
8 Completely rural or less than 2,500 urban population, adjacent to a metro area
9 Completely rural or less than 2,500 urban population, not adjacent to a metro area
(Source: Butler and Beale, 1994)
nonmetropolitan counties sharing important economic and
policy-relevant traits, and information about economic and
sociodemographic conditions that differentiate the county
groups. The original typology (1979) summarized the diversity
of rural economic and social conditions among
nonmetropolitan counties as seven major overlapping themes
or types. Four county types reflected dependence on a
particular economic specialization: farming, manufacturing,
mining, and government. Three county types—persistent
poverty, federal lands, and retirement-destination—reflected
other special policy-relevant themes. A residual type, labeled
unclassified counties, included those counties that met the
criteria for none of the types. An update of the typology, using
the same concepts and definitions updated to 1986 (where
possible), was created to show how the economic and social
structure of nonmetropolitan areas changed from 1979. A
substantial increase in the number of unclassified counties in
the 1986 update emphasized the need to consider both
conceptual and methodological changes in the typology that
would maximize its utility during the 1990s. As a result, the
third version of the ERS typology, updated in 1993, has been
revised and expanded (Cook & Mizer, 1994).
This new typology classifies counties designated as
nonmetropolitan in 1993 into one of six non-overlapping
economic types: farming-dependent, mining-dependent,
manufacturing-dependent, government-dependent, services-dependent,
and non-specialized. Where appropriate, counties
were also classified into five potentially overlapping policy
types: retirement-destination, federal lands, commuting,
persistent poverty, and transfers-dependent. The overlaps in the
new system occur infrequently and usually overlaps occur
between two types. In West Virginia, 12 of the 43 counties
have two classifications and three have three. The counties
with three overlaps are all commuting, persistent poverty and
transfers-dependent. The ERS methodology is based on the
premise that understanding specific economic activities and the
sociodemographic attributes of counties will assist in making
the best policy decisions for that county.
The Concept of Frontier
There are various typologies for characterizing a county in
terms of its population concentration. Population density, a
measure of population concentration, is one
component of the rural/urban classifications
discussed above, and is usually used in
conjunction with population size, adjacency to
metropolitan areas, and urbanization (Hewitt,
1992). Population density can be defined as the
number of people per unit area in a society,
region, or country, and is a measure of the
intensity of settlement of a region (Austin et al.,
1987). Population density is determined by
dividing the resident population of a geographic
unit by the land area it occupies, usually
expressed in the US as square miles. In 1992,
densities of counties ranged from 0.15 persons per square mile
in Loving County, Texas to 67,613 persons per square mile in
New York County, New York (HRSA, 1992). The most sparsely
populated areas are often called “frontier” areas. In 1990, two
percent of the US population was living in counties with ten or
fewer persons per square mile. Map 6 illustrates the
distribution of counties considered “frontier” by categorizations
of 6, 8, and 10 persons per square mile. Map 7 shows where
county population density has dropped in recent years to levels
that qualify them as “frontier.”
In modern day discussions of health care provision,
“frontier” is applied at the county level, and can denote from
six to ten persons per square mile; in most cases frontier is
defined as six or fewer persons per square mile. Demographer
Frank Popper found that as late as 1984, using a definition of
six or fewer persons per square mile, there were 394 counties,
constituting 45% of the US land area, that would meet the
standard (Elison, 1986). Given this notion of frontier as
defined by population density, the nation’s frontier is
expanding. From 1980 through 1990, 24 additional counties
fell below the six persons per square mile criterion for
classification as “frontier,” all of which are in the central plains
area of the nation, a region which was characterized by
significant population losses during the last decade.
Interest in frontier areas as a policy classification for
counties emerged in 1985. At this time rural health providers,
public health planners, and U.S. Department of Health and
Human Services staff agreed that frontier areas constituted a
unique setting in terms of service delivery and should be
considered accordingly under different criteria than those used
for urban or rural service areas (Elison, 1986). A Frontier
Health Care Task Force was convened, under sponsorship of
US DHHS Regions VII and VIII, to look at health issues as they
applied to frontier areas and try to identify those characteristics
distinguishing urban, rural and frontier settings in terms of
access to health care services. The work of this task force, in
conjunction with the National Rural Health Association, led to
modified guidelines for the approval of federal assistance to
community health centers in frontier areas. Their guidelines
included these alternative definitions (Elison, 1986):
• Service Area: a rational area in the frontier will have
at least 500 residents within a 25-mile radius of the
10
Table 4. Classification for USDA ERS Typology of
Primary Economic Activity
Six Economic Activities (#) Five Policy Areas (#)
1. Farming-Dependent (556) 1. Retirement Destination (190)
2. Mining-Dependent (146) 2. Federal Lands (270)
3. Manufacturing-Dependent (506) 3. Commuting (381)
4. Government-Dependent (244) 4. Persistent Poverty (535)
5. Services-Dependent (323) 5. Transfers-Dependent (381)
6. Non-Specialized (484)
health service delivery site or within a logical trade area.
Most areas will have between 500-3,000 residents and
cover large geographic areas.
• Population Density: the service area will have six or
fewer persons per square mile.
• Distance: the service area will be such that the
distance from the primary care site to the next level of
care will be more than 45 miles and/or 60 minutes.
For frontier areas, the primary service delivery issue is how
best to overcome geographic distance and spatial isolation
(Cordes, 1985). In many large western counties the nearest
health care facility, a rural hospital, is more than 100 miles
away. After receiving initial emergency treatment there, a
patient may be referred to a tertiary care center another 100-
200 miles away. In many instances, distances of this length can
cause significant problems of access, such as for a pregnant
woman requiring a series of prenatal visits and eventually
delivery. In general, “low population density means that the
scale of operation of the medical system in rural areas will be
noticeably smaller and different than in urban areas. Indeed, it
is this characteristic that often leads to fundamental and
intrinsic differences in the way health services are delivered,
including the use of airborne ambulances, telecommunication
linkages between remote outposts and secondary care centers,
and satellite care centers staffed with physician assistants and
nurse practitioners” (HRSA, 1992).
Other Federal Systems for
Classification
There are many other systems of classification used by the
many federal agencies. Although this report does not deal with
all of these definitions, it is instructional to read some of these
classification systems in order to see how specific and detailed
they may become when they attempt to accommodate the
many variations and combinations encountered in the structure
of the US. An example of such a very specific and detailed
definition is that used by the U.S. Department of Housing and
Urban Development (HUD) which says: “ ‘rural’ and ‘rural area’
mean any open country, or any place, town, village, or city
which is not (except in the cases of Pajaro, in the State of
California, and Guadalupe, in the State of Arizona) part of or
associated with an urban area and which (1) has a population
not in excess of 2,500 inhabitants, or (2) has a population in
excess of 2,500 but not in excess of 10,000 if it is rural in
character, or (3) has a population in excess of 10,000 but not
in excess of 20,000, and (A) is not contained within a standard
metropolitan statistical area, and (B) has a serious lack of
mortgage credit for lower and moderate-income families, as
determined by the Secretary and the Secretary of Housing and
Urban Development.” (42 U.S. Code, 8A. III. §1490)
Other systems and definitions will undoubtedly be
developed to meet the needs of programs and policies. The
availability of high speed computers, detailed boundary files,
and geographic information systems that can easily calculate
distances and spatial relationships make it possible to tailor
definitions to better reflect the intentions of policy makers and
meet the needs of rural populations.
11
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12
13
Table 5. US Bureau of the Census, State Rural Populations, 1990
State Total Population Rural Population Percentage Pop. Rural
ALABAMA . . . . . . . . . . . . . . . . . 4,040,587. . . . . . . . . . . . . . . . . . . . 1,603,072 . . . . . . . . . . . . . . . . . . . . . . . . . 39.7
ALASKA . . . . . . . . . . . . . . . . . . . . 550,043 . . . . . . . . . . . . . . . . . . . . . 178,808 . . . . . . . . . . . . . . . . . . . . . . . . . 32.6
ARIZONA . . . . . . . . . . . . . . . . . 3,665,228 . . . . . . . . . . . . . . . . . . . . . 458,255 . . . . . . . . . . . . . . . . . . . . . . . . . 12.5
ARKANSAS . . . . . . . . . . . . . . . . 2,350,725. . . . . . . . . . . . . . . . . . . . 1,092,704 . . . . . . . . . . . . . . . . . . . . . . . . . 46.5
CALIFORNIA . . . . . . . . . . . . . 29,760,021. . . . . . . . . . . . . . . . . . . . 2,217,370 . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4
COLORADO . . . . . . . . . . . . . . . 3,294,394 . . . . . . . . . . . . . . . . . . . . . 578,850 . . . . . . . . . . . . . . . . . . . . . . . . . 17.6
CONNECTICUT . . . . . . . . . . . . 3,287,116 . . . . . . . . . . . . . . . . . . . . . 686,512 . . . . . . . . . . . . . . . . . . . . . . . . . 20.9
DELAWARE . . . . . . . . . . . . . . . . . 666,168 . . . . . . . . . . . . . . . . . . . . . 179,011 . . . . . . . . . . . . . . . . . . . . . . . . . 26.9
D.C. . . . . . . . . . . . . . . . . . . . . . . . 606,900 . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0
FLORIDA . . . . . . . . . . . . . . . . 12,937,926. . . . . . . . . . . . . . . . . . . . 1,968,819 . . . . . . . . . . . . . . . . . . . . . . . . . 15.2
GEORGIA . . . . . . . . . . . . . . . . . 6,478,216. . . . . . . . . . . . . . . . . . . . 2,381,672 . . . . . . . . . . . . . . . . . . . . . . . . . 36.8
HAWAII . . . . . . . . . . . . . . . . . . 1,108,229 . . . . . . . . . . . . . . . . . . . . . 122,711 . . . . . . . . . . . . . . . . . . . . . . . . . 11.1
IDAHO . . . . . . . . . . . . . . . . . . . 1,006,749 . . . . . . . . . . . . . . . . . . . . . 428,271 . . . . . . . . . . . . . . . . . . . . . . . . . 42.5
ILLINOIS . . . . . . . . . . . . . . . . 11,430,602. . . . . . . . . . . . . . . . . . . . 1,760,316 . . . . . . . . . . . . . . . . . . . . . . . . . 15.4
INDIANA . . . . . . . . . . . . . . . . . 5,544,159. . . . . . . . . . . . . . . . . . . . 1,947,953 . . . . . . . . . . . . . . . . . . . . . . . . . 35.1
IOWA . . . . . . . . . . . . . . . . . . . . 2,776,755. . . . . . . . . . . . . . . . . . . . 1,093,693 . . . . . . . . . . . . . . . . . . . . . . . . . 39.4
KANSAS . . . . . . . . . . . . . . . . . . 2,477,574 . . . . . . . . . . . . . . . . . . . . . 764,726 . . . . . . . . . . . . . . . . . . . . . . . . . 30.9
KENTUCKY . . . . . . . . . . . . . . . 3,685,296. . . . . . . . . . . . . . . . . . . . 1,775,417 . . . . . . . . . . . . . . . . . . . . . . . . . 48.2
LOUISIANA . . . . . . . . . . . . . . . 4,219,973. . . . . . . . . . . . . . . . . . . . 1,347,848 . . . . . . . . . . . . . . . . . . . . . . . . . 31.9
MAINE . . . . . . . . . . . . . . . . . . . 1,227,928 . . . . . . . . . . . . . . . . . . . . . 679,572 . . . . . . . . . . . . . . . . . . . . . . . . . 55.3
MARYLAND . . . . . . . . . . . . . . . 4,781,468 . . . . . . . . . . . . . . . . . . . . . 893,402 . . . . . . . . . . . . . . . . . . . . . . . . . 18.7
MASSACHUSETTS . . . . . . . . . . 6,016,425 . . . . . . . . . . . . . . . . . . . . . 946,798 . . . . . . . . . . . . . . . . . . . . . . . . . 15.7
MICHIGAN . . . . . . . . . . . . . . . . 9,295,297. . . . . . . . . . . . . . . . . . . . 2,740,098 . . . . . . . . . . . . . . . . . . . . . . . . . 29.5
MINNESOTA . . . . . . . . . . . . . . 4,375,099. . . . . . . . . . . . . . . . . . . . 1,319,082 . . . . . . . . . . . . . . . . . . . . . . . . . 30.2
MISSISSIPPI . . . . . . . . . . . . . . . 2,573,216. . . . . . . . . . . . . . . . . . . . 1,362,110 . . . . . . . . . . . . . . . . . . . . . . . . . 52.9
MISSOURI . . . . . . . . . . . . . . . . 5,117,073. . . . . . . . . . . . . . . . . . . . 1,601,108 . . . . . . . . . . . . . . . . . . . . . . . . . 31.3
MONTANA . . . . . . . . . . . . . . . . . 799,065 . . . . . . . . . . . . . . . . . . . . . 378,998 . . . . . . . . . . . . . . . . . . . . . . . . . 47.4
NEBRASKA . . . . . . . . . . . . . . . . 1,578,385 . . . . . . . . . . . . . . . . . . . . . 534,427 . . . . . . . . . . . . . . . . . . . . . . . . . 33.9
NEVADA . . . . . . . . . . . . . . . . . . 1,201,833 . . . . . . . . . . . . . . . . . . . . . 139,986 . . . . . . . . . . . . . . . . . . . . . . . . . 11.6
NEW HAMPSHIRE . . . . . . . . . . 1,109,252 . . . . . . . . . . . . . . . . . . . . . 543,644 . . . . . . . . . . . . . . . . . . . . . . . . . 49.0
NEW JERSEY . . . . . . . . . . . . . . 7,730,188 . . . . . . . . . . . . . . . . . . . . . 819,867 . . . . . . . . . . . . . . . . . . . . . . . . . 10.6
NEW MEXICO . . . . . . . . . . . . . 1,515,069 . . . . . . . . . . . . . . . . . . . . . 410,443 . . . . . . . . . . . . . . . . . . . . . . . . . 27.1
NEW YORK . . . . . . . . . . . . . . 17,990,455. . . . . . . . . . . . . . . . . . . . 2,827,903 . . . . . . . . . . . . . . . . . . . . . . . . . 15.7
NORTH CAROLINA . . . . . . . . . 6,628,637. . . . . . . . . . . . . . . . . . . . 3,293,044 . . . . . . . . . . . . . . . . . . . . . . . . . 49.7
NORTH DAKOTA . . . . . . . . . . . . 638,800 . . . . . . . . . . . . . . . . . . . . . 298,146 . . . . . . . . . . . . . . . . . . . . . . . . . 46.7
OHIO . . . . . . . . . . . . . . . . . . . 10,847,115. . . . . . . . . . . . . . . . . . . . 2,809,558 . . . . . . . . . . . . . . . . . . . . . . . . . 25.9
OKLAHOMA . . . . . . . . . . . . . . . 3,145,585. . . . . . . . . . . . . . . . . . . . 1,015,777 . . . . . . . . . . . . . . . . . . . . . . . . . 32.3
OREGON . . . . . . . . . . . . . . . . . 2,842,321 . . . . . . . . . . . . . . . . . . . . . 839,123 . . . . . . . . . . . . . . . . . . . . . . . . . 29.5
PENNSYLVANIA . . . . . . . . . . . 11,881,643. . . . . . . . . . . . . . . . . . . . 3,690,922 . . . . . . . . . . . . . . . . . . . . . . . . . 31.1
RHODE ISLAND . . . . . . . . . . . . 1,003,464 . . . . . . . . . . . . . . . . . . . . . 140,324 . . . . . . . . . . . . . . . . . . . . . . . . . 14 .0
SOUTH CAROLINA . . . . . . . . . 3,486,703. . . . . . . . . . . . . . . . . . . . 1,581,345 . . . . . . . . . . . . . . . . . . . . . . . . . 45.3
SOUTH DAKOTA . . . . . . . . . . . . 696,004 . . . . . . . . . . . . . . . . . . . . . 348,271 . . . . . . . . . . . . . . . . . . . . . . . . . 50.0
TENNESSEE . . . . . . . . . . . . . . . 4,877,185. . . . . . . . . . . . . . . . . . . . 1,908,212 . . . . . . . . . . . . . . . . . . . . . . . . . 39.1
TEXAS . . . . . . . . . . . . . . . . . . 16,986,510. . . . . . . . . . . . . . . . . . . . 3,348,809 . . . . . . . . . . . . . . . . . . . . . . . . . 19.7
UTAH . . . . . . . . . . . . . . . . . . . . 1,722,850 . . . . . . . . . . . . . . . . . . . . . 222,989 . . . . . . . . . . . . . . . . . . . . . . . . . 12.0
VERMONT . . . . . . . . . . . . . . . . . . 562,758 . . . . . . . . . . . . . . . . . . . . . 381,797 . . . . . . . . . . . . . . . . . . . . . . . . . 67.9
VIRGINIA . . . . . . . . . . . . . . . . . 6,187,358. . . . . . . . . . . . . . . . . . . . 1,893,128 . . . . . . . . . . . . . . . . . . . . . . . . . 30.6
WASHINGTON . . . . . . . . . . . . . 4,866,692. . . . . . . . . . . . . . . . . . . . 1,149,173 . . . . . . . . . . . . . . . . . . . . . . . . . 23.6
WEST VIRGINIA . . . . . . . . . . . . 1,793,477. . . . . . . . . . . . . . . . . . . . 1,145,608 . . . . . . . . . . . . . . . . . . . . . . . . . 63.9
WISCONSIN . . . . . . . . . . . . . . . 4,891,769. . . . . . . . . . . . . . . . . . . . 1,680,037 . . . . . . . . . . . . . . . . . . . . . . . . . 34.3
WYOMING . . . . . . . . . . . . . . . . . 453,588 . . . . . . . . . . . . . . . . . . . . . 159,042 . . . . . . . . . . . . . . . . . . . . . . . . . 35.1
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