The illiteracy rate in the US is really quite incredible, with the federal government reporting something like 20% of the population to be "low literacy"
Wow - I really thought the first gp in this thread must be wrong, and then researched the UK and we are similar - around 20 to 25 percent. Blows my mind - it appears the levels haven't changed much since the 40s in the UK - which shocked me.
https://nces.ed.gov/datapoints/2019179.asp