Neither java, nor .net broken out?
Is this really about software development? Or the use of rather arbitrarily defined language groupings?
They are not bedfellows.
The defining characteristic of C# is the .net runtime, which it shares with any other .net languages that have no apparent similarity with C. This is similar with Java, the defining characteristic is the java runtime, which is shared with all the other languages that can run on the jvm., although it is not as well publicized, as the Java language is so dominant.
As hinted at in a previous comment (my uncle is called ALAN . .), managed code (.NET and Java, along with many scripting environments) and unmanaged code (C/C++ et al) address very different concerns, and this should form part of the analysis, otherwise you are missing fundamental parts of todays software development landscape.
Lumping C# in with C/C++ is, at best, showing a lack of understanding of what C# is, and at worst, lying with stats.
Missing out java is frankly bizarre (but I'm a Java dev, so I'll admit I'm biased on that one).