In 1877 and 1878, the last two years the 20 cent series was struck, only proofs were made, with 510 of the former date and 600 of the latter. Today, the 1877 and 1878 proof-only 20 cent coin are highly scarce and valuable, as they are sought after by collectors who wish to assemble date runs of the short-lived series. The 1875 and 1876 proofs, with 1,150 of the earlier and 1,200 of the latter, are the most common proof specimens.
Cameo and deep cameo proofs as well as pieces with brilliant fields are the scarcest proofs and command strong premiums over standard prices. However, all proof 20 cent coins are scarce and treasured numismatic relics.