America's transportation system continues to change along with the population, work force, and economy. The following table puts those changes in perspective:

Excel | CSV

Context 1990 2006
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, as of Oct. 2007. GDP-USDOC, Bureau of Economic Analysis, available at, as of Oct. 2007. Population, number of households, and median household income-USDOC, Census, available at, as of Oct. 2007. Average household income and expenditures, and labor force-U.S. Department of Labor, Bureau of Labor Statistics, available at, as of Oct. 2007. Life expectancy-Centers for Disease Control and Prevention, available at, as of Oct. 2007.