Since the first Forever Stamp was issued in April 2007, 28 billion have been sold, the agency said.
Americans honored with commemorative stamps in 2011 will include Ronald Reagan, Mark Twain, Gregory Peck and Helen Hayes and Latin music stars Selena, Carlos Gardel, Carmen Miranda, Tito Puente and Celia Cruz.
The late Rep. Barbara Jordan of Texas will be the 2011 Black Heritage honoree. Stamps will be issued to observe the 150th anniversary of the Civil War, the 50th anniversary of America's first manned spaceflight and Pixar movie characters.
New designs also will be issued for Purple Heart, Wedding and Holidays stamps in 2011.