3-3 U.S.-NAFTA Merchandise Freight Trade by Mode: 2015
a Export weights for land modes are estimated by the Bureau of Transportation Statistics using value-to-weight ratios derived from import data. b Includes 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 Transportation Statistics, special tabulation and North American Transborder Freight Data, available at www.bts.gov as of October 2016.