The study analyzed US traffic data sets taken from August 2011 to February 2012 out of the Chitika Ad Network (covering hundreds of millions of ad impressions).
The data shows that the web market shares of iOS and OS X have been converging steadily since August. iOS has been posting regular gains, and has experienced an overall growth of nearly 50%, whereas OS X has seen its market share decline by 25% since a high point in September. February marks the first point where a reversal in position can be seen in the respective operating systems. iOS passes Mac OS with 8.15% of all web traffic, whereas Mac OS only sees 7.96%.
Check out the chart below...