2008 Liberty Bell Forever First Class Postage Stamps

The USPS has issued non-denominated postage in the past. In 1975, they were unsure when and how much the postage might increase, so they issued that years Christmas stamps without denominations. That saved them from having to print hundreds of millions of stamps with a new denomination. The rate increase, from 10 to 13, occurred just after Christmas.

As postal costs increased, the USPS began to increase their rates for the various classes of mail. Before becoming effective however, these rate increases had to be submitted to the Postal Rate Commission (PRC) for approval. Often, the PRC would take as much as a year conducting studies and compiling data before accepting or rejecting the changes. If the rate increase was approved, the postal service then had to rush to design and produce the new stamps.