What scares me is Safari's Usage is higher than the Mac usage. Does that mean people are using the old Safari on Windows?
Safari (20.4%) Probably not an issue of Safari for Windows, but not accounting for the mobile users. That sums to 25.8% so around 5.4% of Mac + iOS users are using something other than Safari (the vast majority of that is likely Mac users).
(5.4% / 25.8% = 20.9%)