> ie. at least 99% of the Windows users

I bet a lot more than 1% of Windows users have touch screens at this point, since they've become more-or-less standard on high-end laptops.

Mind, it still could easily be < 10%, given how many people have old/cheap PCs.

I don't quite know what the solution is though. The last thing Windows 10 needs in addition to its two separate control panels, command lines, and web browsers are two separate calculator apps.