Market Watch 
July 31, 2013
The Commerce Department  has made changes to how it calculates gross domestic product, designed to have the data better reflect the so-called knowledge economy. The U.S. government adjusted data all the way back to 1929, and other countries have or are about to make similar changes to their data. Read more about the U.S. economy during the second quarter. 
At the same time, the government also went back and revised data for the past five years, to reflect more complete as well as additional statistics from a variety of sources, such as theInternal Revenue Service  and the U.S. Department of Agriculture.
What’s the upshot? The rate of growth hasn’t changed all that much, though there are big shifts in a few time periods. But the level of output is higher — $559.8 billion larger, with $526 billion of that amount due to definitional changes.