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
Currency were valid for temporary use in a small regional territory. In the 10th century, the Song dynasty government began to circulate these notes amongst the traders in its monopolized salt industry. The Song government granted several shops the right to issue banknotes, and in the early 12th century the government finally took over these shops to produce state-issued currency. Yet the banknotes issued were still only locally and temporarily valid: it was not until the mid 13th century that a standard and uniform government issue of paper money became an acceptable nationwide currency. The already widespread methods of woodblock printing