I was recently tasked with interviewing over 50 programmers for a senior position where they would be working mostly with PHP.
I tossed the fizzbuzz problem on the screening exam, mostly to amuse myself and because I wanted ten good questions and had only nine. My intent, at the time was to show people that we can have fun too, even on interview questions.
80% Of the applicants solved the problem, but did not use the modulus operator.
15% of the applicants could not solve the problem.
5% of the applicants solved the problem using the modulus operator.
While my sampling is quite limited (50 applicants from one country), I can tell you that:
95% of them had a BS or higher in a CS curriculum (universities here compete by trying to make CS sound more spectacular).
I was truly amazed. Well, frightened .. but amazed. I did not think I'd come close to reproducing the results, since the problem has become so popular. This shows me that 5% of my applicants might not be super programmers, but at least they read programming related blogs.