1950s Celebrate the Century Sheet of Fifteen 33 Cent Stamps Scott 3187 CELEBRATE THE CENTURY COMMEMORATIVE STAMP SERIES *USPS SET #6(1950s) *6. 1950s - FAMILY, SUBURIA and NUCLEAR THREATS The "Celebrate The Century" series by the USPS was issued in 1998. Noting various important events in the 20th century in the United States.