NOTE: Real gross domestic product (GDP) and total merchandise trade are in
chained 1996 inflation-adjusted dollars.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics,
based on data from U.S. Department of Commerce, Bureau of Economic Analysis,
National Income and Products Accounts, available at http://www.bea.doc.gov/bea/dn1.htm,
as of March 2002.