The value of trade between the United States and its North American trading partners rose in May compared to a year ago, reports the Department of Transportation.

U.S.-NAFTA trade totaled $103.9 billion in May 2014, 5.4% more than a year ago. U.S.-NAFTA trade has increased from the same month of the previous year for four consecutive months and in 10 of the last 11 months, interrupted by a 0.2% decrease in January. The January decline reflected the severe weather in the northern states and along the U.S.-Canada border.

Four of five transportation modes carried more than in May a year ago, led by pipeline, up 23.1%. The increase in the value of freight carried by pipelines reflects both a rise in the volume and prices for oil and other petroleum products and was almost all between the U.S. and Canada.
 
Trucks, the most heavily utilized mode for moving goods to and from both U.S.-NAFTA partners, saw the value of NAFTA freight increase 3.8%. Trucks carried 59.9% of U.S.-NAFTA trade in May 2014, accounting for $31.8 billion of exports and $30.4 billion of imports.
 
The value of U.S.-Canada trade by truck rose 2.7%. Trucks carried 53.9% of the $57.7 billion of freight to and from Canada.
 
The value of U.S.-Mexico trade by truck was up by 4.9%. Trucks carried 67.3% of the $46.3 billion of freight to and from Mexico. The top commodity category transported between the U.S. and Mexico in May 2014 was electrical machinery, of which 91.7% moved by trucks.

This data is reported each month by the DOT's Bureau of Transportation Statistics.