Real gross domestic product -the output of goods and services produced by labor and property in the United States -increased at an annual rate of 4.9% in the third quarter 2007, according to final estimates released by the Bureau of Economic Analysis. In the second quarter, real GDP increased 3.8%.   ; The acceleration in real GDP growth in the third quarter primarily reflected accelerations in exports, in PCE, and in private inventory investment that were partly offset by an upturn in imports, a larger decrease in residential fixed investment, and a deceleration in nonresidential structures.   ; The increase in real GDP in the third quarter primarily reflected positive contributions from exports, personal consumption expenditures (PCE), private inventory investment, nonresidential structures, federal government spending, equipment and software, and state and local government spending that were partly offset by a negative contribution from residential fixed investment. Imports, which are a subtraction in the calculation of GDP, increased.