what things contribute to its economy?
The U.S. GDP and the gross world product.
United States
 U.S. GDP 
who wants to be a millionaire american winner John Carpenter who is he? He  is an American game show contestant and Internal Revenue Service agent. what is he known for? He is best known for becoming the first top-prize winner on the United States version of "Who Wants to Be a Millionaire". which are the different mode of transport in the country mentioned above? Non-two wheel motor vehicles and  airplanes
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United States [SEP] Economy
According to the International Monetary Fund, the U.S. GDP of constitutes 24% of the gross world product at market exchange rates and over 19% of the gross world product at purchasing power parity. The United States is the largest importer of goods and second-largest exporter, though exports per capita are relatively low. In 2010, the total U.S. trade deficit was . Canada, China, Mexico, Japan, and Germany are its top trading partners. From 1983 to 2008, U.S. real compounded annual GDP growth was 3.3%, compared to a 2.3% weighted average for the rest of the G7. The country ranks ninth in the world in nominal GDP per capita and sixth in GDP per capita at PPP.