BEIJING, Jan. 22 -- China's state-level economic and technological development zones have been an important platform for opening-up, stabilizing foreign trade and investment, the Ministry of Commerce said.

In 2021, foreign trade in the 217 development zones evaluated by the ministry totaled 8.9 trillion yuan (about 1.31 trillion U.S dollars), accounting for 22.8 percent of China's total foreign trade, data from the ministry showed.

In particular, trade of high-tech products in the development zones reached 3 trillion yuan in 2021, contributing more than a quarter to the country's total high-tech trade volume.

Foreign direct investment in these development zones, in actual use, stood at about 38.2 billion U.S. dollars, making up 22 percent of the country's total, the data showed.

The development zones boasted stronger scientific and technological innovation capabilities, the evaluation showed, with the number of R&D institutions at or above the provincial level rising to 10,400 as of the end of 2021.

Official data showed that the combined gross domestic product of these zones came in at 12.8 trillion yuan in 2021, contributing 11 percent to China's total.