The United States is Mexico’s largest trading partner and largest foreign investor. Mexico is the third largest U.S. trading partner after Canada and China, and is the U.S. second largest foreign supplier of petroleum. The U.S.-Mexico border is one of the busiest, most economically important borders in the world, with nearly one million legitimate travelers and nearly a billion dollars worth of goods legally crossing the border each day. The deep integration of the U.S. and Mexican economies has resulted in a cross-border production system that enhances the competitiveness of both countries. To put this in perspective, Mexico and the U.S. do as much business in just over a month as Mexico does with all 27 countries of the European Union combined in a year.