Market Intelligence Report |Executive Summary In 2018, there were approximately 15.5 million people in the United States with an intellectual or developmental disability (I/DD) – about 4.75% of the total U.S. population. The proportion of the U.S. I/DD consumer population in the age group of 19 to 64 years increased slightly – from 8.6 million in 2014 to 8.7 million in 2018, while the age group from 5 to 17 years decreased slightly from 2.63 million in 2014 to 2.62 million in 2018. According to our analyses, in 2018, total public expenditures for . . .