The twelve-cent Prexie
The twelfth President was Zachary Taylor, who served from March 5, 1849 until his death on July 9, 1850. His likeness on the twelve-cent definitive stamp of 1938 was taken from a bust in the Virginia State Capitol. Twelve-cent Prexies were only issued in sheet format.
The first release of the twelve-cent Prexie was on September 14, 1938. A total of 664,333,800 were issued through 1959.
The twelve-cent Prexie had very few single-rate usages, all fourth class.
Other single-rate solo uses involved half-ounce airmail postage to El Salvador, Guatemala, Honduras and Nicaragua.
Twelve cents was the cost of a local special delivery letter early in the period, as well as a special delivery postcard to Canada. For a short time in the late 1950's it was also the rate for third class mail with minimum insurance.
Other solo uses include multiple first class and double airmail postage, and parcel post rates for more than one pound.