More than 10 percent of the 16 billion tons of freight moved on the nation's transportation system is international, either entering the country as imports or intended for export, according to International Trade and Freight Transportation Trends, a new report released by the U.S. Department of Transportation's Bureau of Transportation Statistics. 

Almost 71 percent of the international freight tonnage in 2001 was from imports – up from 65 percent in 1997 – and the remaining 29 percent from exports.  

Maritime shipping – which hauls more bulk, low-value goods – carried the largest percentage of U.S. international trade in 2001: 78 percent by tonnage and 38 percent by value. 

Aviation is used for high-value cargo, with 28 percent of the value but less than 1 percent of the tonnage of U.S. international trade moving by air. Trucking carried 21 percent in 2001 by value.  

While all modes were affected by the September 11 attacks, the 13 percent drop in 2001 in the value of air freight activity was the largest decrease of all modes, followed by trucking at 8 percent, maritime at 3 percent and rail at 2 percent. 

Other report highlights:

• More than 19 million containers were used to transport imports in 2001 – 6 million by ocean vessels and 13 million by truck and rail from Canada and Mexico – showing the challenge of maintaining transportation security while facilitating efficient freight flows.
• The transportation-related goods deficit was more than $75 billion in 2001, with a $100 billion deficit in automotive vehicles and parts offsetting a $24 billion surplus in aircraft, spacecraft and parts trade and smaller surpluses in other transportation sectors.
• The United States, the world leader in trade of transportation services, had its annual surplus in this trade transformed into a deficit in 1998 and the following three years as U.S. imports carried by foreign carriers increased and U.S exports growth slowed due to the robust growth in the U.S. economy and the strength of the dollar during this period.
• The ratio of the value of United States imports and exports to gross domestic product increased to 22 percent in 2001, up from 13 percent 11 years earlier. This trend highlights the substantially increasing role of international trade in the U.S. economy.