The most possible answer might be more boring though: this number is increasing because more people are installing Linux in old PCs and Laptops, either out of curiosity or because they want the machine to live more years.
Still, this might make people consider install Linux in their main machine too in the future (after they pass the learning curve).
I guess I'm not in the majority, but my reason for finally switching fully to linux after 20 years is that gaming finally Just Works (mostly) thanks to Wine and Valve. I've been gaming under Linux since Quake III, but always kept a windows install because lots of games ran poorly or not at all under linux.
Last year I finally switched to an AMD GPU, and all the games I've played since then worked either OOTB or required minimal effort to fix (I don't play multiplayer games except for Overwatch, which also runs fine). I haven't booted my windows install in like 6 months, soon I'll wipe it to make some room for more linux games.
Win 10 IOT Enterprise LTSC will be my last Windows. I'm fairly sure Linux will be significantly greater in 2032, so I can avoid this spyware trash. Unfortunately my area of expertise is C#/.NET, so I'm stuck with this trash at work when I will be a working citizen.
In personal experience there has been a big rise of Linux on the server and more people being forced to get used to it. Docker is pushing this along even more now. We are seeing the continued rise in osx and improvements in the Linux desktop. Moving away from windows is becoming more acceptable now, even in corporations. This will continue!
Pace of adoption also seems to be accelerating , from 2009 to about 2016 it went from 0.5 to 1,5 (+ 1 percent), from 2016 to 2023 it went from 1.5 to 3 (+1.5 percent), the adoption also seems to be at least doubling about every decade (which might indicate a "word to mouth" growth pattern.
Something to keep in mind with these graphics are that the scales are hugely different and more notably that the numbers do not add to 100%. Also the percent vs percentage point thing mentioned by @VonReposti@feddit.dk.
It doesn't say how they measure it. Some browsers identify as using Windows. Many people also use multiboot with Windows. Having Windows preinstalled also doesn't mean you're using it.