U.S. Mint Sets (1947-Date): Beginning in 1947, the Treasury Department began packaging and selling sets of Uncirculated coins from that year. Unlike Proof sets, which contain specially prepared coins, Uncirculated sets contain coins made for regular circulation. Each set contains at least one each of every denomination from each of the issuing mints (from 1947 to 1958, Uncirculated coin sets contained two of each denomination from each of the issuing mints).