Energy consumption by China, the world's leading emitter of C02, rose 3.9 percent in 2012 from the previous year but fell by 3.6 percent per unit of gross domestic product, the government said.

The country used the equivalent of 3.62 billion tonnes of coal, the National Bureaus of Statistics reported in a paper on the state of the economy published Friday.

Coal represents 66.4 percent of the total energy consumed, with oil and natural gas accounting for 18.9 percent and 5.5 percent respectively, according to an estimate by the Diyi Caijing economic daily.

The rest is mainly provided by hydro while nuclear power still accounts for a very low proportion of China's energy mix, despite a major programme to construct atomic power plants.

The NBS said in 2012 Chinese consumption of coal rose 2.5 percent, oil 6.0 percent and natural gas 10.2 percent while electricity use climbed 5.5 percent.

Energy consumption per unit of GDP however fell 3.6 percent, it said.

China has pledged to reduce its greenhouse gas emissions by 40 to 45 percent per unit of GDP by 2020 compared to 2005 levels, rather than in absolute terms.

The world's second largest economy is expanding rapidly since it posted GDP growth of 7.8 percent last year, its lowest in 13 years after hitting 9.3 percent in 2011 and 10.4 percent in 2010.