A couple of peaks of unknown seem to match very nicely with the windows graph, if you invert it. I think the two big windows crashes we see are measuring differences or re-categorization effects. … or how about brand new or discontinued versions of windows, that were not counted as windows yet?

German here: you can use “Führer” only with specific other context. There could be for example “Gruppenführer” -> the leader of a group. Or “Anführer” -> could be the elder of a tribe. If you clearly use it in a neutral context, no problem.

But if you use it just like that, it will immediately raise concern if you really meant to say it this way.