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.
Deflator
In the United States, the import and export price indexes produced by the International Price Program are used as deflators in national accounts. For example, the gross domestic product (GDP) equals consumption expenditures plus net investment plus government expenditures plus exports minus imports. Various price indexes are used to "deflate" each component of the GDP to make the GDP figures comparable over time. Import price indexes are used to deflate the import component (i.e., import volume is divided by the Import Price index) and the export price indexes are used to deflate the export component (i.e., export volume is divided by the Export Price index).