Group of 2 United States Mint Proof Sets 1998-1999 10 coins. Group of 2 United States Proof Sets 1998-1999 14 coins. 1998 Set contains 5 Proof Coins, the Kennedy Half, Washington Quarter, Roosevelt Dime, Jefferson Nickel, and Lincoln Cent. Each coin was struck at the San Francisco Mint and carried the “S” mint mark. The packaging for the 1998 Proof Set use the green themed format. The coins were placed into individual slots of a green cardboard holder and sealed in a single lens. The holder was placed in a green card board box within silver printing and a single opening at the top. The 1999 Proof Set began the State Quarters era. Starting this year, five different quarter designs were released annually to honor each of the 50 states in the order they ratified the Constitution or joined the Union. Each set contains the five State Quarters honoring Delaware, Pennsylvania, New Jersey, Georgia, and Connecticut. Completing the set were the 1999-dated Lincoln Cent, Jefferson Nickel, Roosevelt Dime, and Kennedy Half Dollar. All coins were struck at the San Francisco Mint and carry the “S” mint mark. The packaging for the 1999 Proof Set was redesigned to accommodate the additional coins. The cent, nickel, dime, and half dollar were sealed in a single lens with a decorative blue insert. The five State Quarters were sealed in a separate plastic lens. The two lenses were packaged with a certificate of authenticity in a cardboard box with the Statue of Liberty featured prominently.