The 1956-P Roosevelt Dime is one of the more common dates in the series, as it has a mintage of well over 100 million. Examples in circulated grades up to about MS66 without Full Bands characteristics are very common. In MS67 condition they become much scarcer, but yet, easily obtainable at a small premium.
With the Full Bands designation they are scarce in any condition. In MS65 Full Bands they are scarce but not rare by any means. In MS66 Full Bands very scarce. In MS67 Full Bands extremely scarce. Anything higher with the Full Bands characteristics is rare and less than a handful are believed to exist with none grading finer.