The mintage of 704 million coins for the 1964-D is by far the largest of the 1932-1964 silver Washington quarter series. Only the mintage of the 1964 is even remotely close. In fact, except for the 1964, the mintage of the 1964-D is more than five times that of its nearest rival (the 1963-D at 135 million). Still, the 1964-D is less common in Gem condition than several of the S Mints of the 1940s and 1950s. Though a lot of coins were made in 1964, they apparently weren't made and/or handled very carefully.