You're joking...right? The question isn't if something is available, it's what's already being used. Installing Linux would require you to boot from a flashdrive or install it on virtualbox, both of which for most people are unnecessary as shown by the statistics on % of operating systems people use.
What's the Linux % statistics of crypto currency miners? That's the only relevant statistics. Whether your grandma uses Linux or Windows is irrelevant.
That's the whole point, there is no statistics on the % of cryptocurrency miners that use Linux. The only source we have to look at is the % of overall people on this planet that use Linux/Windows, with more than 90% of all computers using the windows operating system...
No we don't have to look at that source, and we actually should not look at it either as it's irrelevant. Similar to your list of nodes at a certain point of time.