So it seems like people do still use 8.1, and I decided to go about finding rough estimates.
As of January 2020, there are 1.2 billion Windows PCs on the internet. We will use that data for our estimates.
As of today, the current marketshare of each Windows version is:
Win10: 66.64%
Win7: 18.49%
Win81: 2.57%
Win8: 0.5%
WinXP: 0.48%
WinVista: 0.07%
95, 98, ME, NT and 2000 are all at 0.00% marketshare, meaning it is probably a very small number.
If we use our percentages with our total # of Windows PCs, we get:
Win10: 1.3 billion (as of Mar 2021), not calculated with the total becuase our latest data for that was before 10 hit 1 billion
Win7: 221.8 million
Win81: 30.8 million
Win8: 6.0 million
WinXP: 5.7 million
WinVista: 840,000
(Assuming marketshare of 0.01%) Legacy: <120,000
Meaning that around 30.8 million use 8.1, and 6 million use 8.0. This is not exact numbers, these are rough estimates.
Lets go deep into the specific Win10 versions. We have 1507, 1511, 1607, 1703, 1709, 1803, 1809, 1903, 1909, 2004, 20H2, 21H1, and Insiders to find. According to AdDuplex, per 70K computers it is:
Insider: 0.7%
21H1: N/A
20H2: 40.1%
20H1: 40.6%
1909: 11.1%
1903: 3.3%
1809: 1%
1803: 1.4%
1709: 1.0%
1703: <1%
1607: <1%
1511: <1%
1507: <1%
If 1.3 billion devices run 10, we get:
Insider: 9.1 million
20H2: 521 million
20H1: 527 million
1909: 144 million
1903: 42.9 million
1809: 13.0 million
1803: 18.2 million
1709: 13.0 million
>1703: <13 million
Why get this data? Just to see actually how many computers you are in a pool with on the internet.