According to http://www.zdnet.com/blog/btl/apple-iphone-smartphone-market... in the first quarter of 2010 Apple had 16.1% of smartphones and smartphones were 18.8% of mobile phones. That comes out to almost exactly 3%.
Ballmer also wasn't wrong about Windows Mobile. The "60 percent or 70 percent or 80 percent" was not a prediction, it was just what he would prefer.