|All other commodities||23.7|
|Ores, slag and ash||2.9|
|Paper and paperboard||3.4|
|Iron and steel||3.7|
|Motor vehicles and parts||4.3|
|Wood and articles of wood||6.0|
|Salt, stone, lime and cement||9.0|
|Mineral fuels, oils and waxes||39.2|
NOTE: These data reflect U.S. import and export trade with Canada and Mexico. Weights of export shipments by land modes are not collected in the administrative records that provide U.S. trade data. The Bureau of Transportation Statistics has estimated the land mode export tonnage using value-to-weight ratios derived from imported commodities.
SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, Transborder Freight Data, as of April 2006.