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
Complementary currency Time Banking inventor Edgar S. Cahn, Complementary Currency Resource Center coordinator Stephen DeMeulenaere and many others. Lietaer has argued that the world's national currencies are inadequate for the world's business needs, citing how 87 countries have experienced major currency crashes over a 20-year period, and arguing for complementary currencies as a way to protect against these problems. Lietaer has also spoken at an International Reciprocal Trade Association (IRTA) conference about barter. Others include: Complementary currency A complementary currency is a currency or medium of exchange which is not a national currency, but which is thought of as supplementing or complementing