Actually, the number of German citizens (or ex-German-citizens, given that German Jews were stripped of citizenship) executed by the Third Reich was "only" about 200,000-300,000 [1], which was about 0.3-0.4% of the population (~70 million). So sort of in the ballpark of "1%", but not even close to 2-3 million, given the much smaller population.

Lots more killing of non-German citizens, of course...

[1] https://en.wikipedia.org/wiki/German_casualties_in_World_War...