Starting in 1965, the U.S. Mint no longer made coins for circulation in 90% silver. Dimes and Quarters were made in copper-nickel. The only coin that continued to be made in silver was the Kennedy Half Dollar which was made in 40% silver for circulation only in 1965, 1966, 1967, 1968, and 1969. This set includes all five of these 40% silver coins. After 1969, no circulating coins of any denomination were ever made in silver again. All later coins were made only in copper-nickel. The 1965-1969 Kennedy Half Dollar are also the only 40% silver coins of any denomination ever made for circulation. In 1970, uncirculated (non-proof) half dollars were struck only at the Denver mint and were available solely in mint sets. Each years circulating edition was made with only one mint mark, so this five-coin set is the absolute complete set of 40% silver Kennedy Half Dollars made for circulation. The 1965-1967 coins bear no mint mark (Philadelphia Mint) while the last two were made at the Denver Mint and have the D mint mark. The first Kennedy Half Dollar was minted in 1964 as a tribute to President John F. Kennedy, who was assassinated in Dallas, Texas, on November 22, 1963.