South Korea's energy imports inched down last year from a year earlier, mostly due to lower demand for crude oil, customs data showed Thursday.

According to the data from the Korea Customs Service, South Korea's energy imports shrank 0.7 percent on-year in 2013. Crude oil imports dropped 4.8 percent, while those of coal and natural gas rose 0.8 percent and 7.7 percent, respectively.

The overall decline in energy imports is attributable to lessened demand for crude oil from industry and the transportation sector, the KCS said.

The rise in coal and natural gas imports, meanwhile, was due in part to increased per-capita consumption of heating fuel, the agency explained.

Of the total energy imports, coal accounted for 42.8 percent, with crude oil and natural gas making up 41.7 percent and 15.6 percent, the data showed.

Saudi Arabia, Kuwait and United Arab Emirates were the sources of 61.8 percent of the total crude oil that the country brought in last year, according to the data. (Yonhap News)