Two items to think about when using German SL numbers:
1. Road salt! Used during the winter, this stuff is horrible on a car, especially on the boxed areas with no interior coating. Once all those boxes start to rot, its not an easy fix. Many places in the world do not use salt, and are also dry. The cars there could survive with higher percentage than in Germany.
2. In 1966, I lived a few months in Germany. This would be 20 years after the war, and right in the middle of Pagoda production. While well on its way to becoming a economic giant of a nation, in many ways Germany was still poor compared to other nations. (my opinion) One could still see the effects of the war in many places. Cars were expensive for the average German, and small scooters, bicycles, and public transit were in heavy use compared to the US. There were few Pagodas to be seen. The exchange rate was in favor of the US, things in Germany were inexpensive for dollars.
Now, 40+ years later, more Germans can afford the SL's and some cars are going back to the homeland. Perhaps this will counter the road salt losses? I hate to think of a dry AZ car, rust free, seeing road salt for the first time, but maybe the cars will be too dear to expose them to such hazards.
So, in reading this thread, I'm guessing there's 30 to 50 percent of the cars left.
Ron