571
Well, this is quite upsetting to read.
(lemmy.nz)
More (not so) fun facts:
54% of American adults read below a 6th grade level.
21% read below a 5th grade level, which is considered functionally illiterate.
High immigration numbers don't fully explain it either, as first gen immigrants only make up about 1/3 of those with low literacy.
Field-specific jargon is so niche that it should hardly count. Even if you're in the same field, you might not be familiar with the tests and metrics they're using if it's not your area of research anyway.