time of the XDR's creation in 1969, the United States dollar was backed by the gold standard and the XDR was fixed at 1/35 troy ounce of gold or exactly 1 US dollar. After the Nixon Shock of 1971 and during the collapse of the Bretton Woods system between 1971 and 1973, the XDR initially remained at 1 US dollar (even as its value relative to gold dropped to 1/38 troy ounce in 1972 and 1/42.22 troy ounce in 1973). On July 1, 1974, the XDR instead became defined by a currency basket of 16 currencies. On January 1, 1981, the five-year schedule was introduced and the XDR basket was reduced to five currencies: the United States dollar, the Deutsche mark, the French franc, the British pound, and the Japanese yen. When the euro was introduced in January 1999, it replaced the German mark and French franc and the basket consisted of four currencies. In November 2010, the IMF determined that the Chinese yuan met the export requirement but failed to meet the "freely usable" requirement and thus was not included in the XDR basket taking effect on January 1, 2011. In November 2015, the IMF announced that the Chinese yuan now met the "freely usable" requirement and would be included in the next basket definition, changing its size back to five currencies. The effective date of the re-evaluation was postponed to October 1, 2016, in order to "allow users sufficient lead time to adjust". In March 2021, the IMF announced that the next re-evaluation, normally scheduled for October 1, 2021, would be postponed to August 1, 2022, in order to prevent the basket's definition from changing during the COVID-19 pandemic. Daily valuation Because of fluctuating exchange rates, the relative value of each currency varies continuously, as does the value of the XDR. The IMF sets the value of the XDR in terms of U.S. dollars every day. The latest U.S. dollar valuation of the XDR is published on the IMF website. For example, on January 31, 2021, the value was US$1.44080, and on June 22, 2021, the value was US$1.426480. Allocations SDRs are allocated to member countries by the IMF. A country's IMF quota, the maximum amount of financial resources that it is obligated to contribute to the fund, determines its allotment of XDRs. Any new allocations must be voted on in the XDR Department of the IMF and