The Kennedy half dollar was struck in 90% silver in 1964. The following year, this was changed to silver-clad, with the silver content lowered to 40%. In 1971, the circulation coinage composition was changed a final time, eliminating the silver, and using the copper-nickel clad standard common to the dollar, quarter, and dime. Bicentennial half dollars dated 1776-1976 were produced in the years 1975 and 1976 in the copper-nickel clad composition for circulation and proof and also in the 40% silver composition in uncirculated and proof versions for inclusion in special collector sets.
