"State or Province" codes seen in US, Canadian, and a few other
addresses. Eg, MT for Montana, ON for Ontario, etc. Includes all the
"wierd" ones that many people don't know, like AA, GU, PW, etc.
This information was compiled from a half dozen websites, as there
didn't seem to be (before this) a good complete list.
Discussed with christos, oster, david, and others.
tsarna