Gross revenue of China's social insurance funds increased 22 percent year on year to 3.14 trillion yuan ($511 billion) in 2012, the Ministry of Finance said on Wednesday.

Gross expenditure increased 27 percent from 2011 to reach 2.39 trillion yuan in 2012, according to the ministry.

China's social insurance funds cover basic endowment for senior citizens, basic medicare, unemployment, work-related injury and maternity.

Gross revenue of basic endowment insurance for retirees of state-owned enterprises, the main part of the basic endowment insurance for senior citizens, reached 1.83 trillion yuan in 2012, up 19 percent from a year earlier. Gross expenditure in this part increased 22 percent from 2011 to reach 1.39 trillion yuan in 2012.

Gross revenue of basic medical insurance for urban employees, the main part of China's basic medical insurance, reached 590.9 billion yuan, up 24 percent year on year. Gross expenditure in this area rose 22 percent year on year to 472.6 billion yuan.

In addition, the gross revenue of unemployment insurance rose 23 percent to 113.9 billion yuan. The gross revenue of work-related injury and maternity insurance stood at 50.6 billion yuan and 29.9 billion yuan, an increase of 13 percent and 39 percent year on year, respectively.