From Calculated Risk blog
'GDP is reported very differently in different countries. In the U.S. the headline number is the real (inflation adjusted) quarterly change, seasonally adjusted at an annual rate (SAAR). In Britain and the EU, the headline GDP number is the real quarterly change, but it is not the annual rate. So a 1.5% decline in the U.K. is about the same as a 6% decline (SAAR) in the U.S.
China reports the year-over-year change in real GDP for the quarter.'