Figure 3,,,,
Domestic Air Revenue Freight Capacity: 1991–2000,,,,
(Billions of ton-miles),,,,
Year,Available freight ton-miles,Unused freight ton-miles,Revenue freight ton-miles,
1991,25.4,16.6,8.7,
1992,26.9,17.2,9.7,
1993,27.8,17.3,10.5,
1994,31.5,19.8,11.6,
1995,33.4,21.0,12.3,
1996,34.8,22.1,12.7,
1997,36.8,23.3,13.4,
1998,38.6,25.0,13.7,
1999,39.6,25.6,14.0,
2000,41.8,27.1,14.7,
"SOURCES: 1991–1995: U.S. Department of Transportation, Federal Aviation Administration, Airport Activity Statistics of Certificated Route Air Carriers (Washington, DC: Annual issues).

1996–2000: U.S. Department of Transportation, Bureau of Transportation Statistics, Airport Activity Statistics of Certificated Air Carriers (Washington, DC: Annual issues).",,,,