The TIOBE index is a chart of what have been rated as the most popular programming languages in the world, according to various searches online, the number of experts in those languages, and even software output (though it is very certainly not a strict chart of "most lines written"). Obviously, it can't be perfect, but it's at least a very simple indicator of what kinds of computer languages developers are using at any given moment.
Look what has appeared at spot number 6: Good old Objective-C, the language that Mac and iOS developers use to code Mac and iOS apps. Mac and iOS development are gaining in popularity lately, thanks to both the Mac and iOS App Stores, and lots of developers are either jumping in to Objective-C development for the first time, or deciding to flex their coding muscles even more (often by leaping into the iOS fray).
This chart shows just how phenomenally Objective-C is growing lately -- just since 2009, developers have started flocking to the platform in droves. That's pretty amazing. Part of it, of course, is that Apple has poured a lot of resources and development time into building up Objective-C and Xcode alike, but I don't think you can overestimate just how powerful the growth of the App Store as a distribution platform has been for Objective-C and its apps.