America's transportation system has changed along with the nation's society and economy. The following table puts those changes in perspective:
|Resident population (thousands)||203,984||281,422|
|Total area (thousands of square miles)a||3,619||3,718 (1990)|
|Total civilian labor force (thousands)||82,771||140,863|
|Real gross domestic productb||$3.4 trillion||$9.2 trillion|
|Median household incomeb||$29,600||$39,200|
|Average household expendituresb||N||$35,384|
|Number of households (thousands)||63,401||104,705|
|Average life expectancy (years)||71||76.7 (1998)|
|Labor force participation by women||46%||60%|
a 1990 data include the Great Lakes and inland and coastal water. Estimate for 2000 not yet available. 1970 data include inland water only. The Census Bureau tabulates area data for the decennial census years only.
Sources: Population, area, number of households-U.S. Department of Commerce (USDOC), Census Bureau, Statistical Abstract of United States: 2000, available at www.census.gov; GDP-USDOC, BEA; median household income-USDOC, Census Bureau, available at www.census.gov/hhes/www/income00.html; expenditures, employment-U.S. Department of Labor, BLS; life expectancy-Centers for Disease Control and Prevention, available at www.cdc.gov/nchs/fastats.htm.