North Korea exported nearly 50 percent less iron ore to neighboring China last year than in 2014, according to Chinese customs data, bringing export revenues for the product to ten year lows.

Iron and ores from mining are one of North Korea’s most valuable exports, after coal and textiles. But while North Korea’s coal exports to China likely benefited from Vietnam’s withdrawal from the market last year, iron exports were not so fortunate.

With falling global prices and slowing demand in China, the DPRK earned just $72 million from its shipments of iron pyrites (otherwise