The preceding version, iOS 6, is still being used by 18 percent of Apple device owners, while just 4 percent use any earlier versions, Apple said.
The numbers were measured by the App Store during the seven-day period ending Sunday, CNET reported, and posted on the App Store Distribution page.
The growth trend of iOS 7 is ongoing; earlier in December it adoption figure was 74 percent, and in mid-October it sat at 64 percent.
A large portion of the rise in iOS 7 installations is likely due to new iOS devices that were given and received over the holidays with iOS 7 preinstalled.
Not all Apple devices are capable of running iOS 7; it is incompatible with iPhones prior to the iPhone 4, iPods before the fifth-generation iPod Touch and the original iPad.
Susan Sarandon 'very excited' about daughter's pregnancy
Scarlett Johansson steps out with fiance after pregnancy reveal