It peaked at 4.05% in March. The last 2 months it went just below 4% as the Unknown category increased. For June the reverse happened, so 4.04% seems to be the real current share of Linux on Desktop as desktop clients were read properly/werent spoofed.
I am still hoping it will hit 10% market share within my life time. I remember when it was predicted to hit that in 2010, obviously it didn’t happen*. Of course for me personally, the year of the Linux Desktop was 2007 when I was finally able to use it as my main OS at home, I tried it before many times since 2003.
* not counting systems that use the Linux kernel but aren’t considered a traditional GNU+Linux desktop.