America's transportation system continues to change along with the population, work force, and economy. The following table puts those changes in perspective:
|Resident population (thousand)||248,791||299,398|
|Total area (thousand sq. mi.)||3,718||3,794 (2000) a|
|Total civilian labor force (thousand)||125,840||151,428|
|Real gross domestic productb (trillion)||$7.1||$11.3|
|Median household incomeb,c||$36,668||$41,350|
|Average household incomeb,c||$39,073||$51,929|
|Average household expendituresb,c||$35,257||$42,204|
|Number of households (thousand)||93,347||114,384|
|Life expectancy at birth (years)||75.4||77.8 (2004)|
a Data for 2000 include inland water, coastal water, Great Lakes, and territorial water. The Census Bureau tabulates area data for the decennial census years only.
b Data in 2000 chained dollars (see Glossary for definition).
c BTS computations, November 2007.
Sources: Area-U.S. Department of Commerce (USDOC), U.S. Census Bureau, Statistical Abstract of the United States: 2002 and 2007, available at www.census.gov, as of Oct. 2007. GDP-USDOC, Bureau of Economic Analysis, available at www.bea.gov, as of Oct. 2007. Population, number of households, and median household income-USDOC, Census, available at www.census.gov, as of Oct. 2007. Average household income and expenditures, and labor force-U.S. Department of Labor, Bureau of Labor Statistics, available at www.bls.gov, as of Oct. 2007. Life expectancy-Centers for Disease Control and Prevention, available at www.cdc.gov, as of Oct. 2007.