From 1996 to 2001, Japan had been Pyongyang’s largest trading partner.

The report said the primary export from North Korea to China was coal between 2008 and 2016. In the early 2000s, its major exports were minerals, such as gold and zinc. It also said North Korea’s coal exports to China surged due to rapid expansion of the Chinese economy.

Rice has been the primary import of North Korea from China, which constitutes 99 percent of the country’s total rice imports.

Another report by the KDI on the North Korean economy in August said it’s suffered a great deal from international sanctions, following a series of nuclear and missile tests. It said one of the reasons the North decided to give up its nuclear weapons program was the economic hardship following brought on by the sanctions.

The volume of trade between North and South Korea surged from 100 million in 1991 to 1.6 billion in 2009, the KDI said. The trade exchange between the North and South constitutes less than 1 percent of the total international trade of South Korea.