The Euro Currency Index (EUR_I) represents the arithmetic ratio of four major currencies against the Euro: US-Dollar, British Pound, Japanese Yen and Swiss Franc. All currencies are expressed in units of currency per Euro. The index was launched in 2004 by the exchange portal Stooq.com. Underlying are 100 points on 4 January 1971. Before the introduction of the European single currency on 1 January 1999 an exchange rate of 1 Euro = 1.95583 Deutsche mark was calculated.