use by them as cost-free alternatives to building foreign exchange reserves through borrowing or running current account surpluses. In 2009, an XDR allocation was made to countries that had joined the IMF after the 1979–1981 round of allocations was complete (and so had never been allocated any). First proposed in 1997, many of the beneficiaries of this 2009 allocation were developing countries. COVID-19 Pandemic On August 23, 2021, the IMF allocated $650 billion worth of XDRs to all 190 members of the IMF in proportion to member quotas in response to COVID-19 related balance of payments concerns. This allocation of XDRs represents roughly 2/3rds of all XDRs currently in circulation, and was by far the largest ever single allocation of XDRs. Value definition Currency basket To determine the composition of the XDR, the IMF takes into account several currencies important to the world's trading and financial systems. A currency's importance is currently measured by two factors: the amount of exports sold in that currency, and whether that currency is considered "freely usable" (determined by its use as a foreign exchange reserve asset and how widely it is used in international transactions). An XDR basket definition remains valid for five years. Approximately one to two months before the end of this time period, the IMF Executive Board will re-evaluate the XDR basket; the currencies included as well as their weights can then change. Changing the XDR's value definition requires at least 70% of the votes among the IMF members. The changes take effect at the end of the five-year period (one to two months after the board review). One business day before taking effect, the newly defined weights are converted to currency amounts based on an average of the exchange rate over the past three months, such that the value of the XDR in U.S. dollars remains the same before and after the change. The currency amounts then remain fixed throughout the five-year period. The IMF reserves the right to perform a re-evaluation after less than five years if it decides that the current basket no longer reflects "the relative importance of currencies in the world’s trading and financial systems"; it also reserves the right to postpone re-evaluations. If either occurs (causing the old definition to be valid for less or more than five years), the new definition will still be valid for a full five years. Historical valuation At the