Released on June 21st, iOS 4 is the newest operating system for the iPhone. In July, one month after its release, it was already powering 50% of all iPhones. Now, based on traffic data from online ad network Chitika, it accounts for 68% of the iPhone market.
Since July 22nd, the previous incarnation, iOS 3, has dropped from 48% of the market to just 31%. Even older operating systems – iPhone OS 1 and 2 – have dropped to a combined 0.7%.