Ron Guth:
Of all the Proof Barber Half Dollars, the date with the smallest mintage is 1914. In that year, employees at the Philadelphia Mint made a mere 380 proof Half Dollars. At today's prices, this is one of the greatest values in American numismatics. Can you imagine what a modern Proof Lincoln Cent with a mintage of 380 pieces would be worth?
The Mint was still favoring Brilliant Proofs over Cameo Proofs in 1914, which may account for the poor sales. As a result, Cameo proofs are very rare and Deep Cameo Proofs are essentially non-existent.