<p>
You are right that IQ scores are calibrated to have a mean of 100. However, the calibration is probably based on a restricted population sample (most likely from an industrialized nation) rather than a global average. Adult IQ scores correlate too much with formal education to be a good measure in third-world countries.</p>
<p>That being said, I think the statistics sound really fishy. I cannot imagine how one would get representative samples of any individual country at all, let alone for so many countries.</p>