<P> The alcohol laws of the United States regarding minimum age for purchase have changed over time . The history is given in the table below . Unless otherwise noted, if different alcohol categories have different minimum purchase ages, the age listed below is set at the lowest age given (e.g. if the purchase age is 18 for beer and 21 for wine or spirits, as was the case in several states, the age in the table will read as "18", not "21"). In addition, the purchase age is not necessarily the same as the minimum age for consumption of alcoholic beverages, although they have often been the same . </P> <P> As one can see in the table below, there has been much volatility in the states' drinking ages since the repeal of Prohibition in 1933 . Shortly after the ratification of the 21st amendment in December, most states set their purchase ages at 21 since that was the Voting age at the time . Most of these limits remained constant until the early 1970s . From 1969 to 1976, some 30 states lowered their purchase ages, generally to 18 . This was primarily because the voting age was lowered from 21 to 18 in 1971 with the 26th amendment . A lot of states started to lower their minimum drinking age in response, most of this occurring in 1972 or 1973 . Twelve states kept their purchase ages at 21 since repeal of Prohibition and never changed them . </P> <P> From 1976 to 1983, several states voluntarily raised their purchase ages to 19 (or, less commonly, 20 or 21), in part to combat drunk driving fatalities . In 1984, Congress passed the National Minimum Drinking Age Act, which required states to raise their ages for purchase and public possession to 21 by October 1986 or lose 10% of their federal highway funds . By mid-1988, all 50 states and the District of Columbia had raised their purchase ages to 21 (but not Puerto Rico, Guam, or the Virgin Islands, see Additional Notes below). South Dakota and Wyoming were the final two states to comply with the age 21 mandate . The current drinking age of 21 remains a point of contention among many Americans, because of it being higher than the age of majority (18 in most states) and higher than the drinking ages of most other countries . The National Minimum Drinking Age Act is also seen as a congressional sidestep of the tenth amendment . Although debates have not been highly publicized, a few states have proposed legislation to lower their drinking age, while Guam has raised its drinking age to 21 in July 2010 . </P>

When did the drinking age become 21 in the us