The answer to this SO question has become stale: iOS version/device statistics - where can i find? because time currency wasn't part of that question, and iOS version updates have been release since this question was asked.

Is there a web site or other publicly available source which keeps a current or frequently updated list of the percentages of iOS devices and OS versions in use, perhaps by continual monitoring of app analytics or web site logs or other means?

And what device or OS information are iOS app analytics currently allowed to report, if any? (...assuming an appropriate privacy policy and adhering to such, of course.)