David Hall: In circulated grades, the 1917-S is rarer than the 1917-D. For the Denver and San Francisco Mints of this era, the D Mints are rarer in circulated grades in 1914, 1916, 1918, and 1919, while the S Mints are rarer in 1913, 1915, and 1917. In Gem condition, things are quite a bit different as the S Mints are rarer than the D Mints for every year from 1913 to 1919 (though only marginally so in 1914 and 1915.) For that matter, the S Mints are rarer than the D Mints in Gem condition for every year from 1913 thru 1928. While strike is a big issue for the S Mints of the 1920s, the S Mints of the 1913-1917 era, including the 1917-S, are often found fairly well struck. The luster for the 1917-S is often frosty and attractive.