BEIJING - China's social security fund saw better-than-average investment performance last year despite downward economic pressure, according to the fund's operator on Friday.

The national social security fund, which pays for social insurance schemes including endowment insurance, raked in about 229.5 billion yuan ($34.88) in investment profits, with the rate of return on investment (ROI) standing at 15.19 percent, almost doubling the average ROI of 8.82 percent since it was established in 2000, according to a report from the National Council for Social Security Fund.

China's social security fund totaled about 1.9 trillion yuan in assets by the end of 2015, with cumulative investment returns of about 790 billion yuan, the report showed.

About 54 percent of its assets were invested via entrusted bodies, while 6 percent of assets were invested overseas, according to the report.