• The proportion of intellectual disability in autism has been decreasing over the past few decades. • Current study examined the proportion of intellectual disability in autism across two decades and in different age groups. • The proportion of intellectual disability in autism decreased substantially over two decades (from 55.8% in 2001 to 6.7 in 2020). • The prevalence of registered autism increased with approximately 800% during the same period.
Salkić et al. (Fri,) studied this question.