North Korea upped purchases of fuel oils in December 2016 to yearly highs, though total spending on imports was lower than in previous years, data from Chinese customs shows.

DPRK importers spent over $17 million on fuels made from crude oil in December, a figure higher than in any other month in 2016. The buying pattern was similar to the previous year’s, where North Korea upped spending on fuels in both November and December.

The increase was mainly due to a large shipment of fuel categorized as “other diesel oils & other fuel oils,” by Chinese customs