Well that was fast. iOS 9 was released on Wednesday and, just 24 hours later, the operating system is installed on 12.6 percent of all iOS devices. That’s according to Mixpanel, which keeps track of these trends and says that 80.29 percent of all iOS devices are still running iOS 8, while the final 7.11 percent are running something older.

It’s pretty impressive for an OS that has been out for 24 hours, but as 9to5Mac notes, iOS 8 was installed on 16 percent of all iOS devices in the same time period. By comparison, however, Android 5.1 Lollipop is installed on 21 percent of all devices, but it was released almost a year ago and Android Marshmallow’s launch is right on the horizon. Apple has a bit of an easier time, however, since it doesn’t need to go through each carrier for approval and only needs to update its own devices, instead of thousands of devices built and sold by thousands of OEMs.

Expect this figure to grow rapidly, especially as the new iPhone 6s and iPhone 6s Plus smartphones launch with iOS 9 preinstalled.