1964-D 10C, FB MS65FB Certification #28681354, PCGS #85129
The circulation strike 1964-D Roosevelt Dime has the highest mintage for any circulation strike Silver Roosevelt Dime produced by the U.S. Mint. It's mintage is also the only one that surpassed the 1 billion mark in the series, as over 1.357 billion 1964-D Dimes were struck.
Despite it's large mintage, coins in MS67 and higher seem to be difficult to find. MS68 examples are almost unheard and probably less than a dozen exist with none being known in better condition.