U.S. #2521
1991 4¢ Make-up Rate
Issue Date: January 22, 1991
City: Washington, DC
Quantity: 1,850,000,000
Printed By: American Bank Note Company
Printing Method: Lithographed
Perforations: 11
Color: Bister and carmine
Although this stamp was criticized for its lack of design, it served a very functional purpose - to "make-up" the 4¢ difference between the old 25¢ rate and the new 29¢ rate. This was the first non-denominated stamp of its kind.