https://webaim.org/projects/screenreadersurvey8/. For me, the three most interesting graphs are:
"Which of the following is your primary desktop/laptop screen reader?"
"When trying to find information on a lengthy web page, which of the following are you most likely to do first?"
"When navigating a web page by headings, how useful are the heading levels (e.g., "Heading 1", "Heading 2", etc.) to you?"
