Simplify the following text for a Grade 13 native English-speaking person.
Original: In the US , 14 % of the adult population is at the `` below basic '' level for prose literacy ; 12 % are at the `` below basic '' level for document literacy ; and 22 % are at that level for quantitative literacy .
Simplified: In the US , 14 % of adults are at the `` below basic '' level for prose literacy ; 12 % are at the `` below basic '' level for document literacy ; and 22 % are at that level for quantitative literacy .