2012 Internet Explorer Firefox Chrome Safari Opera December 14.7 % 31.1 % 46.9 % 4.2 % 2.1 %
I figured down to 30% or so, not < 15%. I think Google's TV campaign must have helped over the last bit. You rarely see Microsoft TV ads except during the Simpsons and Family Guy on Sundays.
Other sources are wildly different; Net Applications, for instance. has IE constantly over 50% and inching up for months. Go figure.
Probably neither is correct, or maybe both are: after all it's an ill-defined problem that doesn't have an unique answer.