The economy of United States of America is a union of 50 states and is third largest economy in the world. By type, it is a mixed economy that means it is a free market economy. Though there is free entry and exit of consumer goods and business services, the government regulates the economy to protect the interest of all. The constitution of America created to protect its mixed economy nature. The U.S. budget is federal with most of its revenue from income taxes. The major expenses go towards three categories – social security benefits, medicare and military spending. The economy of U.S. represents 20% of the total global output and is larger than China. According to IMF, U.S. has sixth highest per capita GDP. It is the second largest manufacturer of higher-value products like automobiles, aerospace, telecommunication, machinery, and chemicals. Agriculture stands only 2% of the output.