肯尼迪半美元
President Kennedy's assassination in November 1963 led to calls to honor him with a place on one of the circulating coins, and the Kennedy half dollar was authorized by Congress on December 30. When 26 million of the new coins were issued on March 24, 1964, they were immediately hoarded, both by investors and by those wanting a memento of Kennedy, and the situation did not ease as more coins were produced. One-third of the record-breaking 202.5 million ounces of silver used in coinage in 1964 thus became coins that did not circulate. Congress allowed the Mint to continue to strike 1964-dated pieces into 1965, hoping to make them not worth putting aside.