No test measures intelligence. A test only measures you relative to the persons that wrote the test. – loosely quoting Asimov.
2007 is ancient history now. It is an interesting graph that one might correlate with a lack of meritocratic structure in society, but I’m on the low end cause I say this without looking up and reading the study. Pretty pictures evoke emotional blabbering bias and all that.
Being smart too.
If your parents are rich you would have gone to the better funded schools with better teachers and better clubs/programs and focus on those with your stress-free lifestyle to grow up smarter.