Following approximately four-and-a-half months of availability, iOS 7 is now installed on 80 percent of devices connected to the App Store, according to the newest numbers posted on Apple's App Store support page for developers.
In early December, iOS 7 usage was at 74 percent, jumping to 78 percent later in December, while iOS 6 usage first declined to 22 percent and then to 18 percent.
Apple's data, which comes directly from the App Store, represents the most accurate iOS 7 adoption information for developers.
Article Link: Apple's App Store Usage Numbers Put iOS 7 Adoption at 80%