Jelly Bean still remains on 60.8% of Android devices; KitKat up to 8.5%
4.2 and 4.3) is on a majority of devices powered by Google's open source OS. The percentage of phones and tablets driven by Jelly Bean is 60.8%. Perhaps the biggest shocker is that there are more devices currently running Gingerbread (Android 2.3.3 through 2.3.7) than Ice Cream Sandwich (Android 4.0.3 through Android 4.0.4).
The data was collected from visitors to the Google Play Store over the last seven days ended May 1st. As far as Android 4.5 is concerned, earlier this year there was speculation that Google would bypass an introduction at the annual Google I/O developer conference, and would instead announce the next major build of Android during the following month.
source: Google via AndroidCentral