That's current android version use. Just over 7% on ICS in 7 months. iOS 5 was 61% in 15 days...not sure what current numbers are off the top of my head.
If you'll pardon the pun, that's kinda apples and oranges.
Apple control their hardware, so backwards compatibility is relatively easy for them compared to the multi-vendor Android arena. They have three closely related handsets to code for, as opposed to countless different Android handsets. Updates for older handsets rely on a) them being up to running it and b) the vendor putting in the effort to continue to develop for that handset. (HTC have now committed to guaranteeing upgrade support for a period of time on newer handsets, incidentally)
From the link there, most Android devices are running Gingerbread. It's not immediately apparent from the version numbers (as you've got tablet-only ones in there) but that's only one major revision behind the current ICS. That doesn't really surprise me; ICS has only been released for a subset of phones so far, for reasons as per my previous paragraph.
Not that I'm really sure why it matters, anyway. Android has always had a rolling take-up, it's the nature of the beast; it was the same story back when I had my first Android phone, only the numbers were smaller.