"Table 11 
Investment in Rolling Stock as Percentage of GDP by Mode, 1977-2000",,,,,,,,,,,,,,,,,,,,,,,,
,1977,1978,1979,1980,1981,1982,1983,1984,1985,1986,1987,1988,1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000
Highways/Transit,5.07,5.32,4.89,3.95,4.02,3.95,4.40,4.82,5.31,5.48,5.15,4.81,4.83,4.36,4.11,4.51,4.82,4.81,4.83,4.53,4.71,4.94,5.05,5.03
Air,0.23,0.24,0.32,0.33,0.27,0.24,0.23,0.19,0.20,0.23,0.24,0.24,0.18,0.24,0.26,0.26,0.23,0.17,0.20,0.18,0.20,0.24,0.33,0.33
Water,0.29,0.27,0.30,0.25,0.26,0.21,0.16,0.18,0.16,0.17,0.18,0.18,0.17,0.15,0.14,0.11,0.12,0.12,0.13,0.13,0.14,0.14,0.14,0.17
Railroad,0.14,0.17,0.22,0.20,0.11,0.07,0.04,0.06,0.05,0.04,0.03,0.04,0.06,0.06,0.05,0.05,0.05,0.06,0.07,0.07,0.07,0.08,0.08,0.07
"Sources: 
BTS calculations based on data from U.S. Department of Commerce, Bureau of Economic Analysis (BEA), ""Fixed Assets and Consumer Durables,"" ""National Income and Product Account (NIPA) Tables,"" available at http://www.bea.gov, as of July 2002.",,,,,,,,,,,,,,,,,,,,,,,,