BEIJING, Dec. 28 (Xinhua) -- China's medium-sized, small and micro enterprises made important contributions to the country's economic development during the 2014-2018 period, official data showed.

At the end of 2018, the number of medium-sized, small and micro enterprises rose 115 percent from 2013 to 18.07 million, making up 99.8 percent of all legal entities, according to a report on China's fourth economic census released by the National Bureau of Statistics.

Those enterprises employed around 233 million people, accounting for 79.4 percent of all enterprise employees nationwide, the report said.

Total annual operating revenue of those enterprises stood at 188.2 trillion yuan (about 26.9 trillion U.S. dollars) in 2018, accounting for 68.2 percent of that from all companies in the country.

Privately-owned medium-sized, small and micro companies boomed during the period, with the number surging 166.9 percent from 2013 to 15.27 million at the end of 2018, accounting for 84.4 percent of all enterprises.

Nearly 40 percent of those firms operated in the central and western regions of the country while those in the eastern region kept the advantage in generating operating revenue, said the report.

China has provided continuous support to the growth of those firms, including lowering financing costs and improving the operating environment.