Quarters have evolved from the early Draped Bust and Capped Bust designs through the Seated Liberty, Barber, Standing Liberty, and Washington types. The 50 State Quarters Program (1999-2008) sparked unprecedented interest in coin collecting, followed by the America the Beautiful and American Women series. Like dimes, quarters transitioned from 90% silver to copper-nickel clad in 1965. Standing Liberty Quarters (1916-1930) and earlier types are especially prized by collectors.