The Kennedy Half Dollar was introduced in 1964, closely following the assassination of President John F. Kennedy. The new half dollar design cut short the life of the prior Franklin Half Dollar, which had not yet run through its required 25 year stint.
For the initial year of release for the new series, the coins were struck in a composition of 90% silver. In the following years, the silver content of the coin was reduced. A composition of 40% silver was used for half dollars issued from 1965 to 1969. The silver content was completely phased out of the denomination starting in 1971.
Despite high mintages for the half dollars of this date range, superb gem examples graded MS67 or higher are difficult to find and command strong premiums. For the proof and special mint set issues of this era, coins are desirable and rare with deep cameo or ultra cameo finishes.