When Congress authorized the Franklin silver half dollar in 1948, it was expected to be issued for at least 25 consecutive years. But following the tragic loss of President Kennedy, Congress quickly approved a new 1964 Kennedy half, abruptly supplanting the Franklin series. The series proved to be America's last half dollar to be completely struck in traditional silver. Unlike current circulating coins, each Franklin half dollar was produced from 90% silver. Just 5.1 million Franklins were produced in Philadelphia in 1957, well over a half century ago. Almost four times as many Denver issues were struck that year making the Philadelphia halves a tougher find.