BEIJING — China's ascension as the world's second-largest economy last year underlines its rise as a major global economic power and potentially a confident, more assertive political power.

China's economy grew a faster than expected 10.3 percent in 2010 from a year earlier, government data showed Thursday, adding further proof that the emerging economic powerhouse has overtaken Japan as the world's second-largest economy.

The value of China's gross domestic product for last year totaled 39.80 trillion yuan on a nominal basis, or about $6 trillion, the National Bureau of Statistics said.