BEIJING — China has sped up efforts to transform from a coal-oriented structure to a cleaner and more diversified energy-production structure over the past 40 years, according to a report released by the National Bureau of Statistics.

Natural gas reached 148 billion cubic meters, and primary electricity came to 1.8 trillion kilowatt hours in 2017, data showed.

The share of clean energy production saw continuous growth. Natural gas made up 5.4 percent of the total energy production, while electricity and other clean energy jumped to 17.4 percent last year, the highest since 1978, said the report.

China’s net energy import also followed an optimized trend last year with the import of raw coal down 1.2 percent and natural gas up 18.4 percent compared with that of five years ago.