It can happen. A slight uptick in the US. Simply because Apple is a US based company. Yet Worldwide, my facts are still correct. It's well below 5%. So low that it's not even considered relevant enough to be listed.
http://en.wikipedia.org/wiki/Usage_s...rating_systems
"In August 2011, Gartner estimated Apple's PC market share in US as 10.7% for Q2 2011. Apple's worldwide market share is not listed, because not in top 5; inferred to be 5% or below. Gartner's numbers include netbooks, but not media tablets such as the iPad. Total units in Q2 2011 from all vendors, ~85 million.[3]"