The following are my predictions for the one year adoption rate of future Android versions (+/- 2.5%):
Android Oreo, 9%
Android P, 15%,
Android Q, 19%
Android R, 22%
Android S, 24%
Android T, 25%
Android U, 25%

Android Oreo reached 14.6% by end of August 2018- beyond the 11.5% margin of error. It will be fun to track future Android version adoption rates, I hope my predictions prove to have wildly underestimated Project Treble.