I don't know. The 20 number sounds correct for 1975. Remember, in January there was a fire that destroyed just about every car plus the entire factory. Production didn't restart until April and wasn't back to normal until late 1975. Plus I think I remember something about most of the post-fire 75's being 3000M's for Europe. 946 2500M's were made from 1972-1977 worldwide, and while the car was marketed primarily to the US, it was not the only place it was sold. I think I remember reading year by year production figures along with markets, maybe Marshall (mrtvr) has this in one of his books?