Yo, I'm actually the Data Analyst who worked on this. Turns out a poorly constructed regex put all of C# and C++ into C. We've addressed this and will be putting out a revised edition of the report by the end of the week.
Interesting counterpoint to this is jQuery. Their jQuery book came out very early in the game and was authored by people very much involved in the project. Some of the jQuery API docs are actually based on the book.