People can select multiple editors, so you can't sum them like that. E.g. people on windows could use Visual Studio AND Notepad++. All this says is that at least 10% use Mac because xcode only runs on the Mac, and at least 32% use Windows.
Oh, all the questions accepted multiple answers? Ok makes sense now... then they can't add up to 100. Still the OS question is flawed because multiple answers means it's not their primary OS.
