The 53% number is for a very narrow period of time: the 12 weeks ending on Nov 25, 2012, which just coincides with the release of iPhone 5...

IOW: nothing to see here, move along. Like jacalata pointed out, the average market share of iOS, measured on a longer period of time, is closer to 35%: http://mashable.com/2013/01/04/apple-smartphone-market-share...