"During a Slovak study in the 90's, 23 510 childred in the age of 6 – 14 years in the district of Banská Bystrica, Slovakia, were given a Wechsler Scale test. A total of 510 children (2,16 %) were diagnosed as mentally retarded (with an IQ 70 or less). 0,9 % of the non-Gypsies were diagnosed as mentally retarded, as opposed to 21,5 % Gypsies. Although the Gypsy children constituted only 6 % of the testing sample, they counted for 60,7 % of the mentally retarded"