$40 billion
note: North Korea does not publish any reliable National Income Accounts data; the datum shown here is derived from purchasing power parity (PPP) GDP estimates for North Korea that were made by Angus MADDISON in a study conducted for the OECD; his figure for 1999 was extrapolated to 2006 using estimated real growth rates for North Korea's GDP and an inflation factor based on the US GDP deflator; the result was rounded to the nearest $10 billion (2007 est.)