This article brings us up to date on  The state of the browser war as we enter 2013 (Graeme McMillan, Digital Trends, Jan 2.)

• Internet Explorer has slipped to 54.53% of the US market – mostly IE9 – people have not been converting to IE10. Amazingly some people are still using IE6.
• Firefox dropped to 19.66%
• Chrome rose to 18.44%

I recommend using all three.