1978 - Orange "A" Eagle stamp

When the Postal Service (PS) wanted a rate change it had to be approved by the Postal Rate Commission (PRC).  The PRC would sometimes take as long as a year (collecting data, conducting studies, etc.) before approving/rejecting the hike.  In 1975 the PS was waiting for approval to go from 10 cents to 13 cents.  Christmas was coming up.  The PS printed their first NVI (No Value Indicated) stamps - the contemporary and religious Christmas stamps that year had no denomination on them.  Those stamps sold for 10 cents.  Approval to go to 13 cents came on December 31.  After that the PS decided to think ahead.  They printed up a number of NVI stamps w/ just a letter indicating the value and put them aside for later.  The 'A' stamp went into use a few years later when the price of stamps was approved to go up to 15 cents.  This definitive stamp was first issued in May 22 1978 in Memphis, Tennessee.  The practice of using a letter for a denomination continued through to the "H" series.  Eventually, the PS converted to the current 'Forever Stamps'.