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 mun
The mun was introduced as the main currency of Korea in 1633 and stayed in use until 1892. It resembled and was derived from the Chinese wen (cognate also to the Japanese mon, Ryukyuan mon, and the Vietnamese văn). Coins denominated in mun were cast in copper or bronze and were round with square holes. From the 17th century until the end of the 19th century, coins denominated in "mun" bearing the inscription "Sangpyeong Tongbo" (, ) were the most widely circulated currency. In 1888, coins were struck in small numbers denominated in mun and won (equal to 1000 mun). The mun was replaced in 1892 when the yang was introduced.