The 1964 United States Proof Set is a "One Year Type Proof Set" that is almost 40 years old. 1964 was the only Year that the Proof Kennedy Half Dollar was made in 90% Silver. Since the United States Mint has starting selling Silver Proof Sets in 1999, their value has been steadily increasing, with the most recent sets starting at $37.95. When you consider the 1964 Silver Proof Sets in the light of these facts, "THEY ARE A GREAT VALUE!" Sure to increase in the future.