Ron Guth:
In 1878, the Carson City Mint struck the last Dimes it would ever produce. As a "going-away" present, the Mint dropped the mintage of the Dimes to a mere fraction of those of the preceding years, this making the 1878-CC the sixth smallest mintage out of nine dates (counting each of the two types of 1873). Thus, the 1878-CC Dimes enjoys strong demand from collectors of products from this popular Mint.
In Mint State, the 1878-CC Dime is scarce and expensive but not inaccessible. Grades above MS64 are truly rare, and the finest example is a remarkable PCGS MS68 (most likely the Eliasberg coin).