Where can I find data about the United States' trade with other countries?
The U.S. Census Bureau makes Foreign Trade Statistics available online. Among other things, you will find statistics on the value of U.S. imports and exports with countries around the world. The available data ranges in age from a few months to several decades or more in some cases.
For more information on researching international trade, take a look at this guide from the Pomerantz Business Library.