<prompt> Most common type of mental retardation -MildModerateSevereProfound  <response>: The number of mild cases far exceed the severe and profound cases English statistics suggest that among 100 mentally handicaped persons 70 mild, 20 moderate, 5 severe cases WHO classification of Mental retardationMR mild MR...IQ 50-70 moderate MR ...35-49 severe MR..IQ 20-34 profound MR...IQ under 20 ref; page no;582 23rd edition of PARK;s textbook of Preventive and Social medicine 