BEIJING - China's State-owned enterprises (SOEs) saw their profit growth quicken in the first three quarters on the back of an improving economy, official data showed Friday.

Combined SOE profits rose 24.9 percent year-on-year to 2.2 trillion yuan ($332.8 billion) for January-September, the Ministry of Finance said on its website.

The growth was higher than the 21.7-percent expansion seen in the first eight months.

Business revenue of the companies totaled 37.6 trillion yuan, up 15.9 percent from one year earlier. Their operating costs went up 15 percent to 36.3 trillion yuan during the same period.

By the end of September, the total assets of SOEs stood at 148.9 trillion yuan, while their liabilities reached 98.4 trillion yuan, both up around 12 percent compared with one year earlier.

SOEs in steel and non-ferrous metal sectors continued strong profit growth. Transportation, coal, oil and petrochemical industries enjoyed relatively large profit increases, but power generation firms suffered significant declines, the data showed.

China has thousands of SOEs, but many have become stagnated due to a lack of competition. The government is trying to improve their fortunes through reform, moving toward mixed ownership and market-oriented management to improve efficiency.

According to a State Council action plan released in July, China's major SOEs will complete corporate governance reform by the end of 2017.

The reform targets SOEs supervised by the central government, excluding financial and cultural firms.