How do you rate yourself in C?

This is a tricky question. When I began attending interviews,
my answer used to be a number, say, 5. Actually, the answer
is more than this. If you give a proper explaination and then
arrive on a number, you have impressed the interviewer.
These days, I would answer it in this way:

“I have been learning C since a good time. My learning is
majorly from experimenting small-small programs. I understand
various data types, qualifiers, syntax rules, and program
execution, etc. I also have advanced (or beginner’s) knowledge
of C internals like writing for portability, efficient usage of
C constructs, understanding of pointers, etc. (These details
would change from person to person.) Keeping all these facts
in mind, I can safely rate myself at 6.5.

I am reserving the rest 3.5 for understanding the C grammar,
C99 details and related issues.