Yes, since the question is slightly open, this could refer to target platforms instead of what the actual developers are using on their desktops. Still, a nice-looking datapoint ;)
Anecdotally, as an IT chief I see developers who use Windows struggle with tasks that are simple in Linux and MacOS. There's a reason why a) MacOS won so many developers and why b) Microsoft is spending so many resources making WSL/WSL2.
> For October 2019 the Linux gaming population on Steam according to Valve was about 0.83%, basically flat compared to September, at least on a percentage term. Meanwhile for the newly-published November figures it comes at 0.81%, or a decline of 0.02%.
Hilarious considering it is, by far, the most used desktop operating system. It's almost like there's a reason small languages stay small...