|Mode||Value (percent)||Weight (percent)|
|NAFTA trade, total||100.0||100.0|
|Other and unknowna||4.7||0.3|
|U.S.-NAFTA imports, total||100.0||100.0|
|Other and unknown||2.9||0.1|
|U.S.-NAFTA exports, total||100.0||100.0|
|Other and unknowna||7.2||0.6|
a BTS estimated the export weight for truck, rail, pipeline, and other and unknown based on value-to-weight ratios from the import data, because export weights for surface modes are not currently reported. Weight for water and air exports and imports are from the U.S. Department of Commerce, U.S. Census Bureau.
Notes: Value based on millions of U.S. dollars; weight based on millions of short tons. Percentages may not add to 100 due to rounding.
U.S. NAFTA (North American Free Trade Agreement) refers to U.S. trade with Canada and Mexico, our partners in this agreement.
Sources: Compiled by U.S. Department of Transportation (USDOT), Research and Innovative Technology Administration, Bureau of Transportation Statistics (BTS), October 2007. Water and air data-U.S. Department of Commerce, U.S. Census Bureau, Foreign Trade Division, FT920 U.S. Merchandise Trade: Selected Highlights, December 2006. Total, truck, rail, pipeline, other and unknown data-USDOT, BTS, Transborder Surface Freight Data 2006; and special calculation, October 2007.