(a) Current Dollars
(b) Chained Dollars
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, Federal Gas Tax: Household Expenditures from 1965 to 1995, TranStat, August 1997. 1998 dataU.S. Department of Transportation, Bureau of Transportation Statistics estimates based on U.S. Department of Commerce, Bureau of Economic Analysis, Survey of Current Business, various issues; U.S. Department of Labor, Bureau of Labor Statistics, Consumer Expenditure Survey, 1996, 1997, and 1998; and U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 1998 (Washington, DC: 1999).