This is the first year in which the U.S. Mint struck Washington Quarters to commemorate each of the 50 States. From 1999 to 2008 the Mint struck five different Quarter designs every year to honor each State. The first design was none other than the Delaware design. The Mint struck examples from the Philadelphia and Denver Mint for circulation. It also struck Proof examples at San Francisco.
The 1999-D Delaware Quarter was very easy to find in circulation. Examples in MS66 condition appear to have been scarce but easily obtainable with enough searching in original bags or rolls. In MS67 condition they are very scarce with possibly hundreds if not several thousand examples still being out there. In MS68 condition, it is really scarce and none are known in better condition.