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
The country then had to switch over to a new currency unit named "hwan" replacing won at 1 hwan = 100 won. Like South Korean won, this currency unit was also issued in banknotes initially but in 1959, coins denominated in hwan were also issued and were the first circulating coins in South Korea. Hwan had a peg with US dollar but with time it also got devaluated. This was the reason for the reintroduction of won in 1962 as the official currency unit. South Korean currency was still pegged to the US dollar until in 1997 when it was floated into the world market.