According to new stats from mobile ad network Chitkia, Apple iPad users account for more than 82 percent of all tablet web browsing. Amazon’s Kindle Fire came in a distant second with 6.5 percent, and the Samsung Galaxy Tablets ranked third with 4.7 percent of tablet usage. Though they account for just 0.4 percent of online tablet usage, the Microsoft Surface Tablet dominated the category of “Step Up–style ads featuring office workers breaking into choreographed boardroom dance sequences” …