North Korean coal imports from China increased 100-fold between July and August, according to newly released Chinese customs data.

The new numbers put the amount of coal shipped from China at nearly 45 thousand tonnes, up from just 450 in July. At current prices, the August deliveries will have upped the DPRK’s monthly coal bill to more than U.S. $5 million.

The increase marks the highest levels of coal imports and largest percentage increase since 2011, though no data is available prior to that year. The August total is also far above recent yearly averages, which have been steadily decreasing