From my POV, there's no reliable source of linux usage. It's not like you could count the amount of licenses sold, since it's mostly free to download. You can't count the amount of computers installed with a single downloaded image. The Steam surveys are not held as accurate in linux as they are in windows. etc, etc.
When I buy a computer I'm forced to buy a windows license but I don't use it. I just format the hard drive and install linux. Do I account as a Windows user? So I guess the windows usage tracking is somewhat misleaded.
I truly believe the estimates of linux desktop being just 1% are plainly wrong...but anyway, this might change in the coming decade, since now 96% of servers run on linux, 90% of the tablets and smartphones run on android (based on linux) and Microsoft adding the linux shell in Windows 10...
I'll make a bold prediction here and say in the upcoming 15-20 years Microsoft will drop windows as we know it and release their own flavour of Windows Linux.
