Apple has announced that iOS 8 adoption is now at 77% as measured by the App Store on March 16th. That's an increase of 2% from March 2nd.
iOS 8.x adoption has been increasing slowly but steadily. The release of iOS 8.2 likely assisted in the 2% increase over two weeks. iOS 8.3 has already been seeded to developers for testing.
It's great to see some appreciation but just because it barely increases keeps on constantly updating how very little it keeps coming back with adoption rates.