Sub-Saharan Africa uniformly scores low on all the IQ research aggregated in Murray and Herenstein's(sp?) "The Bell Curve". It would suck to be them, a full standard deviation down. Doh!
Also see Richard Lynn and Tatu Vanhanen, "IQ and the wealth of nations" - their book has much more detailed tabulations.
As I recall (and you had to be paying close attention to find it), sub-Sahara was TWO standard deviations down. African-americans were (roughly) one standard deviation down, but that gap was narrowing. At least that's what I recall.