China's gross domestic product has been understated by as much as US$300 billion, the country's first nationwide economic census has discovered, according to a South China Morning Post report. The sum, equal to nearly 20% of last year's US$1.65 trillion GDP, is said to highlight the serious understatement of data on the nation's expanding services sector, which contributed about 29% to GDP growth last year. It remains unclear how the US$300 billion will be included but it is believed that this and other new census figures will be used to revise economic data for the past 10 years.