To Do have to dig up that long thread on the Steve Jackson Games Forums that dealt with "real life" scores for IQ and DX. I put up the results from memory, here, but we should expand on it.

Realistic Attribute Scores

Realistic scores for IQ range from 9 to 12. 99% of people on Earth would have such scores. 13 and 14 are for really imaginative, creative and incredible people, with 15 being for pure geniuses such as Da-Vinci. Note that famous scientists like Einstein don't have to be modeled with an incredibly high IQ score. They can have a more mundane one, such as 12 or 13 at most, but with several points spent in a Talent for scientific skills. (This paragraph should be greatly expanded - see the To Do property at the top of the page).