Quoting from http://www.tiobe.com/index.php/content/paperinfo/tpci/index....: "The scores for C have been pretty constant through the years, varying between the 15% and 20% market share for almost 10 years. So the main reason for C's number 1 position is not C's uprise, but the decline of its competitor Java."

If you look at the list, Objective-C has also jumped up 31 spots since last April. I'm wondering if a shift toward development for mobile devices (iPhone and otherwise) has caused C to leapfrog Java.