Economy of North Korea
Estimating gross national product in North Korea is a difficult task because of a dearth of economic data and the problem of choosing an appropriate rate of exchange for the North Korean won, the nonconvertible North Korean currency. The South Korean government's estimate placed North Korea's GNP in 1991 at US$22.9 billion, or US$1,038 per capita. In contrast, South Korea posted US$237.9 billion of GNP and a per capita income of US$5,569 in 1991. North Korea's GNP in 1991 showed a 5.2% decline from 1989, and preliminary indications were that the decline would continue. South Korea's GNP, by contrast, expanded by 9.3% and 8.4%, respectively, in 1990 and 1991.
Korean currency
From 1978 to 2001, the North Korean government maintained an iconic rate of 2.16 won to the US dollar; since then banks in the country exchange at rates closer to the black market rate. However, rampant inflation has been eroding the North Korean wŏn's value to such an extent that currently it is believed to be worth about the same as the South Korean wŏn (needs sourcing). In any case, the U.S. dollar and other currencies are still worth more in North Korean wŏn on the black market than officially.