According to the report, at least 71.2% of all development is happening inside Windows or a Windows VM (Visual Studio and Notepad++ are Windows only). Sounds like a lot of folks are using Macs to host a Windows VM, which I see all the time. If you include a small portion of Eclipse, Netbeans, IntelliJ, Xamarin then you're probably approaching 80% of all development being done on gasp Windows.