|Mode||Value (percent)||Weight (percent)|
|NAFTA trade, total||100.0||100.0|
|Other and unknowna||4.4||1.3|
|U.S.-NAFTA imports, total||100.0||100.0|
|Other and unknown||2.4||0.6|
|U.S.-NAFTA exports, total||100.0||100.0|
|Other and unknowna||6.8||2.5|
aBecause export weights for surface modes are not currently reported, BTS estimated the export weight for truck, rail, pipeline, and other and unknown based on value-to-weight ratios from the import data.
Note: U.S. North American Free Trade Agreement (NAFTA) refers to U.S. trade with Canada and Mexico.
Source: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, Transborder Freight Data, available at http://www.bts.gov/programs/international/transborder/ as of September 2011, and BTS special calculation, September 2011.