It is widely discussed how common the syndrome is, as there are figures that show very different numbers. But, it probably lies between 1 in every 250, all the way up to 1 in every 10,000. A 2003 review of epidemiological studies of children found autism rates ranging from 0.03 to 4.84 per 1,000, with the ratio of autism to Asperger syndrome ranging from 1.5:1 to 16:1.