The People's Bank of China, the central bank, said Saturday the country had issued 5.1 trillion yuan (773.3 billion U.S. dollars) worth of bonds in 2010, an increase of 3.1 percent over that in 2009.

National debt, debt issued by policy banks and short-term financing bonds contributed mainly to the bond market expansion last year, said a central bank statement posted online.

The central bank also noted that the total value of bonds in China's inter-bank market soared 21.5 percent year on year to 15.8 trillion yuan at the end of 2010. Last year, the Ministry of Finance issued 1.7 trillion yuan of bonds via the inter-bank market.

Currently, China's inter-bank issuers include the Ministry of Finance, policy banks, Ministry of Railways, commercial banks and other financial institutions.