A worker assembles a robotic arm at a factory in Foshan, Guangdong province. [Photo provided to China Daily]

BEIJING - China's major industrial firms posted stronger profit growth in the first eight months of this year as producer prices went up and production costs came down, the National Bureau of Statistics (NBS) said Wednesday.

Industrial companies with annual revenue of more than 20 million yuan (about $3.02 million) reported profits of 4.92 trillion yuan in the first eight months, a 21.6 percent increase from one year earlier, the NBS said in a statement.

The strong growth marks a pick-up from the 21.2 percent in the January-July period.

In August alone, profits of major industrial firms jumped 24 percent year-on-year, much faster than the 16.5 percent growth in July, the NBS said.

Among the 41 industries surveyed, 39 posted year-on-year profit growth during the first eight months.

NBS statistician He Ping said the strong growth was a result of price hikes in industrial products and lower production costs.

China's producer price index (PPI), which measures costs of goods at the factory gate, rose 6.3 percent year-on-year in August, 0.8 percentage points higher than the July level.

The price rebound has added some 127.3 billion yuan to the August industrial profits, accounting for 31.2 percent of the total profit increase last month, said He.

The trend was particularly evident in sectors such as the petroleum, steel and electronics industries, the statistician said.

In August, the oil and natural gas exploitation industry's profits went up 4.94 billion yuan from a year ago, but in July, it suffered a decrease of 1.03 billion yuan in profits.

Meanwhile, for each 100 yuan of revenue, companies had to spend 85.44 yuan, a 0.64-yuan decrease from the same period last year, NBS data showed.

He also mentioned that the leverage ratio of Chinese industrial firms is on the decline amid the government's ongoing supply-side structural reform. By the end of August, their debt-asset ratio dropped 0.7 percentage points from a year ago to 55.7 percent.

The industrial sector, which accounts for about one-third of China's GDP, started to pick up last year after a bad 2015. The upbeat August profits data has added to evidence of resilience in the sector and steady improvement in the overall economy.

China's value-added industrial output grew 6 percent year-on-year in August, previous NBS data showed. On a monthly basis, industrial production edged up 0.46 percent in August compared to July.

China's economy expanded 6.9 percent for the first half of 2017, above the government's 2017 full-year target of around 6.5 percent.

The Asian Development Bank projected earlier this week that China's economic growth will be 6.7 percent for this year and 6.4 percent for 2018.

In an update of the Asian Development Outlook 2017, its flagship annual economic publication, the bank said better-than-expected external demand, proactive fiscal policy and strong domestic consumption have combined to drive up China's growth.