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.
More realistically, it would be stuff like
The sign over a parking spot says no parking Monday through Friday, 9:00 AM to 5:00 PM. Select the times and dates that you are allowed to park there.
9:30 AM, Tuesday
8:00 PM, Sunday
5:15 PM, Thursday
12:00 PM, Monday