Gross domestic product
Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced in a period of time, often annually 
GDP (nominal) per capita does not, however, reflect differences in the cost of living and the inflation rates of the countries; therefore using a basis of GDP per capita at purchasing power parity (PPP) is arguably more useful when comparing differences in living standards between nations.
United States
The nominal GDP of the U.S. is estimated to be $17.528 trillion . 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 according to the United Nations (first in the Americas) and sixth in GDP per capita at PPP. The U.S. dollar is the world's primary reserve currency.