Imports from Colombia have increased significantly since 1996, from $4.27 billion in 1996 to $8.85 billion in 2005, an increase of 107 per cent. The United States` trade deficit with Colombia amounted to $3.43 billion in 2005.  Since the end of 2006, US products have been burdened with more than $3.4 billion in Colombian tariffs and duties, which would otherwise have been eliminated by the free trade agreement.  The U.S. International Trade Commission estimates that the agreement would increase U.S. exports to Colombia by an additional $1.1 billion per year.  Colombia, which then joined Peru and Ecuador, in which Bolivia participated as an observer, opened free trade negotiations with the United States on May 18, 2004.