Apple's yearly developer conference should see iOS 8, OS X 10.10, and likely some hardware.
Nearly 300 Million Devices Running iOS 6, 60% of All iOS Devices Ever
Of these, perhaps the most impressive is that 300 million devices are currently running iOS 6. That is, as EdibleApple points out, roughly 60 percent of all iOS devices ever sold:
During Apple’s most recent earnings call, Apple CEO Tim Cook said that Apple to date has sold over 500 million iOS devices. If we put those pieces together we see that over half of every iOS device ever sold is now running the most recent version of Apple’s mobile operating system. Contrast that of course to Android where a scant minority of users are ever caught running the most recent iteration of Android.The Next Web notes that Apple sold some 75 million iOS devices in the December quarter alone, all of which are running iOS 6, plus 100 million upgrades to iOS 6 in its first week of availability back in September.
Apple has clearly been successful in keeping devices upgraded to the latest version of iOS, particularly through the over-the-air update feature that was introduced last year in iOS 5. This keeps iOS devices secure, and keeps users up to date with the latest new features to come out of Cupertino.