According to Apple's own data, the adoption rate for iOS 9 has reached 57 percent of iPhone, iPod touch and iPad devices in the wild after three weeks of availability, as measured by the App Store on October 5, 2015. By comparison, it took iOS 8 nearly six weeks to zoom past the 50 percent barrier.
A total of 33 percent of iOS devices running iOS 8Â visited the App Store on October 5, while earlier version of the mobile operating system accounted for the remaining ten percent of hardware in the wild.