The U.S. Mint began selling Mint Sets of every circulated coin issued directly to collectors beginning in 1936. These first U.S. Mint proof sets were made available to collectors, although at that time collectors had to purchase one of each coin on the same order to receive a set. By the 1950s, demand for proof coins rose dramatically from thousands of collectors to eventually hundreds of thousands of coin collectors. Eventually, commemorative coins were added in business strike and proof finishes to increase market demand. U.S. Mint marketing programs created a variety of sets, combining commemorative coins denominations and different finishes targeted directly to collectors. The result? The popularity of  U.S Proof and Mint Sets skyrocketed. Today, the annual Proof, Uncirculated, and Silver Proof sets are highly anticipated releases from the United States Mint.