The chart at right, taken from the Wikipedia entry for Android version history, illustrates the problem app developers call Android fragmentation — the splintering of Google’s (GOOG) installed base into incompatible fragments. Applications that run on one combination of hardware and software don’t necessarily run on others.

Wikipedia doesn’t offer a similar chart for Apple (AAPL) iOS, and the graphic below, created for us by Chitika, suggests why.

Unlike Google, which gives hardware manufacturers license to modify Android, Apple controls both the hardware and the software. That gives Apple two advantages that matter to developers:

• Apple can make it relatively painless for users to upgrade to new versions.
• It can ensure that the new hardware runs the old software, and vice versa.

The result is a considerably less fragmented mobile ecosystem. As of Dec. 1, according to Apple, 96% of iPhone users were running either iOS 6 (22%) or iOS 7 (74%).

LINK: Chitika: iOS Version Distribution Study – 2012 through 2013

UPDATE: To facilitate apple-to-apple comparisons, reader marc (full name withheld) has eyeballed the data and created new versions of the charts in which the colors, the date range and the orientation are roughly the same. I’ve attached them below.