Now remember, that these aren't specifically browsers, these are representations of rendering engines. IE's rendering engine is called Trident, Firefox's is called Gecko, etc. So it's interesting that IE is falling, yes it's still built into every Windows Machine, but the alternative browsers are gaining market in there as well. Look at Firefox, it's up a bit, but the one that is the biggest uptick is Webkit. Webkit is the rendering engine behind Safari (Mac's browser), Chrome (Google's browser), Android's browser, the iPhone browser, and the iPad browser.
Now, I don't know if they counted mobile browsers in this mix (iPhone, iPod, and iPad) but it's an interesting graph none-the-less.
AppleInsider | Internet Explorer web browser use drops below 60%.