This seems to be in line with what we have heard previously where iPhone adoption rates were sitting at 90% and iPad at 85%. Presumably the new number released by Apple covers both the iPhone and iPad and also covers all versions of iOS 7, with the latest version being iOS 7.1.2. That being said these figures are pretty impressive.
Based on the pie chart, iOS 6 is currently on 9% of all iOS devices, while older versions of iOS is sitting at 2%. This is compared to Android where the latest build of Android is less than a fifth of Android devices out there. We expect that when Apple releases iOS 8 later this year, the adoption rate should be a lot faster, if not at the same rate.
This is because unlike iOS 7, iOS 8 does not have many new visual changes but rather builds on top of iOS 7 and introduces new features, so chances are iOS users would be less resistant to the update, or so we hope.