肯尼迪半美元
The Kennedy half dollar is a United States coin that has been minted since 1964. In the first year of production the coins were minted in 90% silver and 10% copper (90% silver). From 1965 through 1970, the coins were minted in a clad composition of mostly silver outer layers and a mostly copper inner layer (40% silver). After 1970, the coins are minted in a copper–nickel clad composition. From 1992 to 2018, 90% silver coins were made for inclusion in special "Limited Edition" silver proof sets. Beginning 2019 coins in the special silver proof sets are produced from pure (.9999) silver.