China\'s statistics authority on Monday revised its gross domestic product (GDP) for 2011 slightly up based on its final verification. The revised GDP was 47.31 trillion yuan (7.52 trillion U.S. dollars), up 22.2 billion yuan from the preliminary verification figure, the National Bureau of Statistics (NBS) said in a statement. The year-on-year growth stayed unchanged at 9.3 percent calculating in constant prices, the statement said. According to international practices, the GDP figure is usually adjusted several times as more statistics become available, the NBS said. The bureau calculates each year\'s GDP three times - preliminary calculation that ends before Jan. 20, preliminary verification that ends before the end of September, as well as final verification before the end of January the following year, the statement said.