Well, it is not a matter of
me putting the Model S in a class with BMW 7, Audi 7/8, S-Class, etc.. It's the German Federal Office for Motor Vehicles which assigns cars into segments/classes, based on some specific aspects. Model S is in the so called Oberklasse-Segment, and there it has a 2.6% market share in Germany. And the numbers I have posted, are official registration numbers from that very federal office with some basic math (extrapolation for the whole year).
Source, if you want to check yourself:
Kraftfahrt-Bundesamt - Startseite