In 1872, Mint employees struck 950 Proof Dimes for potential sale to collectors. A substantial number of Proof examples of this date are available to collectors, mosty in grades from PR62 to PR64. Gems are rare, but not overly so, and even PR66's are available. The top grade appears to be PR67.
This date consists of well-made examples, of which perhaps as much as 20-25% of the population shows Cameo contrast. PCGS has not yet recognixed even a single Deep Cameo 1872 Dime and it is unlikely that they exist at all.