In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.

Passage: However, Berman concurs with many on the right on a number of issues, particularly foreign policy and trade. Berman voted in support of the invasion of Iraq in both 1991 and 2003, as well as for the FISA Amendments Act of 2008, positions that have hurt his standing among many liberals in his district. While he generally supports free trade - for instance, voting in favor of the North American Free Trade Agreement (NAFTA) and various trade agreements with specific countries -, he voted against the more recent Central America Free Trade Agreement (CAFTA). He opposes withdrawing U.S. support for the World Trade Organization. In that same year, he also voted to phase out many farm subsidy programs put into place by the administration of President Franklin Delano Roosevelt as part of the "New Deal."
Link Information: none Answer: none
How many years has the U.S. supported the World Trade Organization?