What are the economic characteristics of the us economy?

The economy of the United States is the world's largest national economy. Its nominal GDP was estimated to be nearly $14.7 trillion in 2010,[1] approximately a quarter of nominal global GDP.[15][16] Its GDP at purchasing power parity was also the largest in the world, approximately a fifth of global GDP at purchasing power parity.[15] The U.S. economy also maintains a very high level of output per capita. In 2010, it was estimated to have a per capita GDP (PPP) of $47,284, the 7th highest in the world. The U.S is the largest trading nation in the world. Its three largest trading partners as of 2010 are Canada, China and Mexico.