Presumably you're asking about variation as a function of SES...? If so, one can eyeball an answer from the top row of figure 2. At the bottom of the SES scale, there're a bit under 500 units (IQ points squared?) of full scale IQ variance (none from additive genetic effects, a bit under 300 units from common environment, and a bit under 200 units from nonshared environment). At the top of the SES scale, there're about 300 units of variance (essentially all coming from additive genetic variance). Note that these numbers all come with wide error bars.