Closing in on 8% if you filter it by “English language only”. Chinese speakers overwhelmingly (almost exclusively) use Windows and make up about 30% of all Steam users, which skews the rest-of-world results. And I wouldn’t consider 8% of all prospective sales to be a joke, especially since that number only keeps on rising and by the time you’ve spent a few years writing a game it’s likely to be quite a bit more.