North Korea’s gross domestic product (GDP) grew by 3.9 percent last year, South Korea’s central bank reported on Friday.

According to the “Estimates of North Korea’s Economic Growth Rate in 2016” report by the Bank of Korea, North Korea’s economy grew primarily in the mining, manufacturing, electricity, gas, and water sectors.

These sectors reportedly saw a 22.3 percent year-on-year growth – a development potentially linked to recent state efforts to promote natural energy.

The mining and manufacturing industries also grew, the Bank of Korea claims, seeing an 8.4 and 4.8 percent increase, respectively, from 2015, mainly fuelled by increased