3-3 U.S.-NAFTA Merchandise Trade by Mode: 2013
aExport weights for land modes are estimated by the Bureau of Transportation Statistics using value-to-weight ratios derived from import data. bIncludes mail, other, unknown, and shipments through Foreign Trade Zones.
Notes: Percents do not add to 100 due to rounding. North American Free Trade Agreement (NAFTA) refers to U.S. trade with Canada and Mexico.
Source: U.S. Department of Transportation, Bureau of Transporation Statistics, special tabulation and North American Transborder Freight Data, available at transborder.bts.gov as of September 2014.