The commenter above is saying that your suggestion that there is some contradiction here indicates a mathematical error. The post claims 60% have read a book; you claim 20% can't read at all; both can be true.
Yeah… I didn’t say they both weren’t true due to a mathematical error… I was insinuating that the survey is probably flawed because if 20% of Americans can’t read… they likely aren’t even taking this survey.
It is also my uneducated guess that the actual percentage of Americans who haven’t read a single book in the past year is MUCH higher than 40%. Maybe a survey of HN commentators but not of the general population.