Recent data has found that South Korea’s underground economy makes up less than 20 percent of the nation’s gross domestic product(GDP).

According to a recent report released by the International Monetary Fund(IMF) on the shadow or underground economy of 158 countries over 1991 to 2015, South Korea’s underground economy accounted for 19-point-83 percent of the nation’s GDP. 

That’s down nearly ten percentage points from 1991 when it hovered at around 30 percent. 

Shadow economy was defined as "all economic activities which are hidden from official authorities for monetary, regulatory, and institutional reasons,” including avoiding paying taxes and governmental bureaucracy or the burden of regulation.

The report found that the underground economy of 158 countries made up 27-point-78 percent of their GDP on average as of 2015, down from 34-point-51 percent in 1991.