I'd only add that I'm quite sure that C++ is more popular than C for compilers. I wouldn't go so far as to say there's a clear majority--there are far more programming languages and compilers in the world than most engineers experience regularly. There
are only a few generally available general purpose PL's, but many more used for specialized types of programming. There was a time that large machines came with their own custom PL's in fact (think telephone switches, factory automation equipment, etc).