Authorities in Mexico seize around 100,000 weapons in the country each year. About 30 percent of the weapons are sent to the United States for analysis, and 80 percent of those are found to have been made in the United States. Please note that this does not mean that the United States was the origin and supplier of these weapons. For example, significant numbers of rocket launchers and grenades are U.S. made, but was supplied into Mexico from Guatemala.
Source: Stephanie Nebehay, “U.S. role in arming Mexico’s drug war exaggerated-study,” Reuters, October 27, 2011.