Today, AdDuplex published its monthly report on Windows 10 and Surface usage. The data is based on the over 5,000 Microsoft Store apps that use the AdDuplex SDK v.2 or higher, and it was collected on June 29.
While the Windows 10 May 2020 Update has been available for over a month now, it's still on only 7% of Windows 10 PCs. Of course, it's been a very slow rollout, and there are still a bunch of issues blocking it. Perhaps more strange is that the year-old version 1903 is still the most popular version, only declining by 2% from last month to 46.2%. Version 1909 declined from 36.4% to 35.7%.
Version 1809 saw the biggest decline from 8.3% to 5.9%, and that's because Microsoft started automatically updating users on 1809 to 2004. This is the new way that Microsoft does things, and it's why newer updates aren't seeing as much traction as they would have in the old days. New feature updates are optional, and you have to opt into them; they're only installed automatically if the version you're on is nearing the end of support, like 1809 is.
That's also evident from the graph showing how fast various updates have rolled out. Version 1809 was particularly problematic, and Microsoft started to make changes after that. That's why versions 1903 and later have slower rollouts than the ones that came before 1809.