Thanks for the comment! I so agree. Here is that source, I believe the data is for the US: https://www.medpagetoday.com/pediatrics/autism/37976

And I just looked it up and found a more recent one: https://www.autismspeaks.org/autism-statistics-asd. I'm glad you asked, I will also add it to the article and specify that these numbers are for the US.