Do you remember a fifth of whiskey, instead of 750ml ?

I recently came upon a trash dump from the 40s and 50s. In it I found a one half pint bottle, a pint bottle and a 4/5 quart bottle.
(Or a fifth of a gallon)
Now we refer to a 200ml as a half pint, a 500ml as a pint and a 750ml as a fifth. then you have a quart, then and a liter, now.
I can remember when the change occurred in the late sixties or early seventies. I wonder if anyone knows a more exact time of the change. I remember being taught in school that the U.S. would go metric. But liquor bottles is the only thing that is commonly labeled that way today.