Just incase anybody wanted to know the average grades/scores that students internationally receive in IB, I've found a PDF with statistics from IBO - this is the most recent PDF I could find and the statistics have been taken from the May 2016 session.
I've listed the page numbers of some information depending on what you may want to check -
Page 9: Extended Essay statistics
Page 10: TOK statistics
Page 16: Statistics on number of points awarded to candidates
Page 17 to Page 22: All subject grade distributions (including mean grade + % of candidates receiving grades)