Hi All,
   I managed to track down a 1970 issue of The World Almanac & Book of Facts.
On page 952: "Gradually replacing the traditional abbreviations for the
states of the U.S. are the two-letter ones approved by the Post Office
Department when it introduced the ZIP Code in [October,] 1963." Then
followed a chart of the official two-capital-letter P.O. abbreviations.
   So... Who wants to define "gradually?" ;-)   A Govt Docs librarian at
I.U. found a reference to 2-letter abbreviations (BUT the example was "Va"
NOT "VA" -- no period though) in a 1967 P.O. bulletin about the new OCR
letter sorting machine.   One person e-mailed the recollection of learning
to address PA as "Penn." in high school in the mid-70s.  Gradual, indeed.
   Chris Bobbitt     [log in to unmask]
   Curator of Collections
   Monroe Co. Historical Museum
   Bloomington, Ind.