Mobile ad firm AdMob today released a bit of data that provides an interesting glimpse into operating system versions being used on the iPhone and iPod touch. According to a survey of ad requests received during the week of September 15th-22nd, just after Apple's release of iPhone OS 3.1, 23% of aggregate users of the iPhone OS had already updated to iPhone OS 3.1. An additional 51% of users were running iPhone OS 3.0, with the remainder running earlier versions of iPhone OS.
Interestingly, AdMob notes that when data is broken out into iPhone versus iPod touch, a full 91% of ad requests from iPhones are from users running iPhone OS 3.0 or 3.1, while only 35% of iPod touch users are running some flavor of iPhone OS 3.0. The disparity highlights the effect of Apple's iPhone OS upgrade fees for iPod touch users, a phenomenon noted in previous reports from AdMob.