Blood Type

For so many years I have wondered what my blood type is, and promptly forgotten again for in reality, how often are you asked about your blood type?
But then Flemming told me about a card we old geezers can get here in Mexico to obtain discounts on a number of things, such as bus tickets ( long distance ) .
So now I again had interest in knowing the blood type since this is required information for the card.
And I made a search on the web for places where one would get this info and in the middle of the quest a thought came to me.
My discharge papers.
Surely they would have that information and I found my dog tag ( I save everything ) and yes, there it was.
I am A pos.
Now I know, and all the time the information was right there, only I did not know where to look.