I suspect accuracy of any IQ test falls off the further you get from 100 in either direction, so I’m not married to any global IQ dataset in particular. But they all show the same trend.

All the politically and economically prosperous countries show as high and the basket cases show as low. And if you sit in on their political discourse it increasingly sounds like you’re in an open air mental institution. (Though regrettably that model has been losing a lot of predictive power in the democratic West lately).