an epidemiological study conducted at Montreal Children's Hospital in the 200–2004 school year found a prevalence rate of 0.68% (or 1 per 147). A 2001 review of the medical research conducted by the Public Health Agency of Canada concluded that there was no link between MMR vaccine and either inflammatory bowel disease or autism. The review noted, "An increase in cases of autism was noted by year of birth from 1979 to 1992; however, no incremental increase in cases was observed after the introduction of MMR vaccination." After the introduction of MMR, "A time trend analysis found no correlation between prevalence of MMR vaccination and the incidence of autism in each birth cohort from 1988 to 1993." United States CDC's most recent estimate is that 1 out of every 44 children, or 23 per 1,000, have some form of ASD as of 2018. The number of diagnosed cases of autism grew dramatically in the U.S. in the 1990s and have continued in the 2000s. For the 2006 surveillance year, identified ASD cases were an estimated 9.0 per 1000 children aged 8 years (95% confidence interval [CI] = 8.6–9.3). These numbers measure what is sometimes called "administrative prevalence", that is, the number of known cases per unit of population, as opposed to the true number of cases. This prevalence estimate rose 57% (95% CI 27%–95%) from 2002 to 2006. The National Health Interview Survey (NHIS) for 2014–2016 studied 30,502 US children and adolescents and found the weighted prevalence of ASD was 2.47% (24.7 per 1,000); 3.63% in boys and 1.25% in girls. Across the 3-year reporting period, the prevalence was 2.24% in 2014, 2.41% in 2015, and 2.76% in 2016. The number of new cases of autism spectrum disorder (ASD) in Caucasian boys is roughly 50% higher than found in Hispanic children, and approximately 30% more likely to occur than in Non-Hispanic white children in the United States. A further study in 2006 concluded that the apparent rise in administrative prevalence was the result of diagnostic substitution, mostly for findings of intellectual disability and learning disabilities. "Many of the children now being counted in the autism category would probably have been counted in the mental retardation or learning disabilities categories if they were being labeled 10 years ago instead of today," said researcher Paul Shattuck of the Waisman Center at the University of Wisconsin–Madison, in a statement. A population-based study in