"How many percent of Germans smoke?"

Translation: Kolik procent Němců kouří?

[BoneheadBass]

This point may have been made in a similar exercise, but "how many percent" just isn't right in English. English speakers generally would use "what percent" or, probably less frequently, "what percentage."

[VladaFu]

Indeed, even the Google books hits are mostly clearly from non-native speakers.