I agree with the author who wrote:
And then there is the rapid rise of Objective-C which underlies Mac OS and iOS.
[It] was barely in TIOBE's top 40 in 2008. But since then, it's climbed rapidly in popularity because people have been using it to write apps for the iPhone and iPad.
I've been looking at Objective-C for a while. An excellent site is at djavupixel.com