Oh, one of the rare months, where Valve lists the GPU shares in total (instead of splitting them up in DX11, DX10, DX9), very nice! This list also contains GPUs with percent shares down to 0.15%, in the DX11-list, all GPUs below 0.30% are hidden in "Other".
The R9-300 series and the Fury series are still not listed, so they are probably still under 0.15%. But the R9-200 series got a good boost (perhaps R9 200+300 are counted together for now):
The GTX 970 also got a good boost from 3.50% (September) to 4.00% and is now officially the most popular GPU on Steam (the Intel 4000 series is down from 3.87% to 3.59%). Neither GTX 950 nor the GTX 980 ti seem to have reached at least 0.15% yet:
IF (and that's a big "if") the account growth on Steam has been steady at 5 million per month, the number of gaming PCs on Steam which can compete with the PS4 power, should be around 30 million by now. I really hope that Valve updates the number of active Steam accounts soon!
Windows 10 has now surpassed 200 million installations (according to the site WinBeta):
http://www.winbeta.org/news/as-2015-comes-to-a-close-windows-10-surpasses-200-million-installs