New Transportation Department figures show June marked the 18th consecutive month the total value of U.S. freight movements with North American Free Trade Agreement (NAFTA) partners Canada and Mexico declined from the same time a year earlier.

The 6.4% drop in the dollar value of freight moved between the countries totaled $92.7 billion as all transportation modes except air carried less cross-border freight by value in June of this year compared to June 2015.

The value of freight carried by truck fell 5.8% while rail movements moved lower by 4.4%. Pipeline and vessel fright posted larger drops, 15.6% and 19.7%, respectively, due in large part to a falloff in the price of crude oil, which accounted for 9.4% of total value of U.S.-NAFTA trade in June.

The value of commodities moving by air increased 5%, mainly due to a 35.6% increase in the value of imports of pearls, precious stones, and metals.

Trucks carried 65.4% of U.S.-NAFTA freight and continued to be the most heavily utilized mode for moving goods to and from both U.S.-NAFTA partners. Trucks accounted for $31.2 billion of the $49.2 billion of imports, or 63.5%, and $29.4 billion of the $43.5 billion of exports, or 67.5%. Rail remained the second largest mode by value, moving 15.2% of all U.S.-NAFTA freight.

Freight Flows With Canada, Mexico Fall

From June 2015 to June 2016, the value of U.S.-Canada freight flows fell 7.2% to $48.2 billion as all modes of transportation except air carried a lower value than a year earlier.

Lower crude oil prices contributed to a year-over-year decrease in the value of freight moved between the two countries. Crude oil is a large share of freight carried by pipeline and vessel, which were down 16.1% and 31.9%, respectively, year-over-year, according to the report.

Trucks carried 60.4% of the value of the freight to and from Canada. Rail carried 15.8% followed by pipeline with 7.9%, air at 4.9% and vessel with 4%.

In June 2016, the top commodity category transported between the U.S. and Canada by all modes was vehicles and parts, of which $5.6 billion, or 57%, moved by truck and $4 billion, or 40.7%, moved by rail. The surface transportation modes of truck, rail and pipeline carried 84.1% of the value of total U.S.-Canada freight flows.

When this past June is compared to the same time in 2015, the value of U.S.-Mexico freight declined 5.5% to $44.5 billion as all modes of transportation except air carried a lower value of U.S.-Mexico freight.

Freight carried by truck fell 5.5% while rail posted a 4.9% decline. Pipeline and vessel freight value dropped by 10.1% and 11.3%, respectively, as air increased 1.3%.

Trucks carried 70.8% of the value of freight to and from Mexico. Rail carried 14.5% followed by vessel with 8.1%, air at 3% and pipeline at 0.7%. The surface transportation modes of truck, rail and pipeline combined carried 86.1% of the value of total U.S.-Mexico freight flows.

The top commodity category transported between the U.S. and Mexico by all modes in June 2016 was electrical machinery, of which $8 billion, or 91.2%, moved by truck.