Essentially the entire Internet and most corporate engineering/R&D runs on Linux Serversand if they were so bold as to include a category of "Servers", things would look very different.
IMO, not including servers is like taking a "Worldwide" market survey Automobiles and only including, say, those manufactured in America.
Don't mind me, I'm cranky. My basement sump pump clogged last night and flooded the basement. Put me in a bad mood to start the day....