Reserve currency before the beginning of the worldwide credit crunch related recession and Eurozone crisis, which harmed the euro and slowed its adoption. Since 2009, the reserve currency use of the euro has continued to drop, down to 23.9 percent in 2013. The Dutch guilder was the "de facto" reserve currency in Europe in 17th and 18th centuries. The United Kingdom's pound sterling was the primary reserve currency of much of the world in the 19th century and first half of the 20th century. The emergence of the USA as an economic superpower, and the establishment of the U.S. Federal Reserve System
Korean currency 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. The Joseon Dynasty issued its first copper coins. In 1888, shortly before the yang was introduced, a small number of coins denominated in hwan (圜) and mun (文) were minted. Even though the yang had been used in past it was reintroduced as the main currency in 1892. One yang was subdivided in 100 fun, making it the first Korean