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
World currency unit and are protected against two key sources of uncertainty, namely inflation and exchange loss risks. World currency unit There are two different types of World Currency Unit in use today that have different origins and usages. The WCU was proposed by Lok Sang Ho of Lingnan University, Hong Kong. The WCU was first intended to be the basis for denominating global bonds, a debt instrument that is issued globally and is subscribable by people and institutions around the world. Simply put, it is a GDP-weighted basket of key currencies each of which is indexed against inflation for the relevant countries.