BEIJING - China's social security fund gained 142.46 billion yuan ($23.2 billion) from investment in 2014, with an 11.69-percent return on investment, according to its annual report on Friday.

The rate of return outperformed the 6.2-percent return in 2013.

Founded in 2000, the fund is designed to solve the country's aging problem as well as serve as a strategic reserve to support future social security spending.

As of the end of last year, the fund's managed assets totaled more than 1.5 trillion yuan.

The fund manager vowed to improve yields this year by strengthening management of investments.

By the end of 2014, the debt balance totaled 78.31 billion yuan despite the overall success of investments, according to the report.