CHANGSHA, Aug. 27 (Xinhua) -- China's top 500 enterprises reported their first annual decline in combined revenues in 15 years with a 0.07-percent drop last year.

Among the top 500 firms, 155 reported declines in revenues in 2015, 61 more than a year ago, with many of them representing the overcapacity-plagued coal, steel, oil and chemicals industries.

Meanwhile, 72 firms reported losses, 15 more than a year ago.

China Enterprise Confederation and China Enterprise Directors Association unveiled the 2016 edition of the Top 500 Chinese Enterprises list Saturday. The list is based on revenues from 2015.

The State Grid grabbed the top spot with 2.07 trillion yuan (310 billion U.S. dollars) in revenue, with oil giants China National Petroleum Corp. and Sinopec ranking second and third.

Haitong Securities, GF Securities and China Galaxy Securities entered the list for the first time as a bull stock market boosted their revenues.

Revenues of the top 500 totaled 59.46 trillion yuan (8.9 trillion U.S. dollars) last year.

The service sector contributed 40.5 percent of the revenues, outperforming the manufacturing sector, at 39.2 percent, for the first time.

Of the 500 firms, 157 are from the service sector, six more than a year ago, and 261 are manufacturers, five less than a year ago.

The 500 companies invested 1.48 percent of their revenues in research and development (R&D) on average, with leading search engine Baidu and telecom equipment supplier Huawei spending 15.9 percent and 15.1 percent on R&D respectively.

Cui Dianguo, chairman of train maker CRRC Corp., said large companies should speed up overseas expansion to create a global value chain.