average intelligence score
110 - 119 - Superior intelligence 90 - 109 - Average or normal intelligence 80 - 89 - Dullness 70 - 79 - Borderline deficiency in intelligence Under 70 - Feeble-mindedness. Normal Distribution of IQ Scores. 50% of IQ scores fall between 90 and 110 70% of IQ scores fall between 85 and 115 95% of IQ scores fall between 70 and 130 99.5% of IQ scores fall between 60 and 140 Low IQ & Mental Retardation An IQ under 70 is considered as mental retardation or limited mental ability. 5% of the population falls below 70 on IQ tests.