List of countries by GDP (nominal)
Gross domestic product (GDP) is the market value of all final goods and services from a nation in a given year. Countries are sorted by nominal GDP estimates from financial and statistical institutions, which are calculated at market or government official exchange rates. Nominal GDP does not take into account differences in the cost of living in different countries, and the results can vary greatly from one year to another based on fluctuations in the exchange rates of the country's currency. Such fluctuations may change a country's ranking from one year to the next, even though they often make little or no difference in the standard of living of its population.
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).