Not that I'd trust any statistic I haven't made up carefully compiled myself I'm surprised that it took so long, what with the rapid proliferation of mobile devices. You'd think the odd Android user would notice that their mobile thingy lets them use the internet with something else than IE and think hey, maybe I can do that on my PC as well.
On a side note: any browser is reasonable fast when you block all the crap you don't need anyway.