The United States is Jamaica's most important trading partner. An important destination for U.S. investment, Jamaica has generally been a supportive partner in efforts – bilaterally, regionally, and globally – to liberalize trade. Under the Caribbean Basin Trade Partner Act and other trade measures, over 80% of Jamaican exports enter the U.S. market duty free. The United States provides over $100 million in support through the Overseas Private Investment Corporation for expanding and diversifying energy sources available on the island. The two countries have an investment treaty and a double taxation agreement. More than 80 U.S. firms have offices in the country and hundreds of other U.S. firms sell their products through local distributors. Over a million American tourists visit Jamaica each year, and hundreds of thousands of Jamaicans visit the United States. The large Jamaican-American community sends billions of dollars in remittances to Jamaica annually.