Maybe if you were to make just a little more effort and consider that a ‘militant’ is not an ‘écrivain’ you would have found it.
Or just not be a fucking annoying American and be too lazy to have learned another language while making confident statements about information in that language.
nces.ed.gov/surveys/piaac/…/national_results.asp
You can look under ethnicity but I haven’t found anything that supports the claim made by OP. I assume it’s just in absolute numbers which doesn’t make sense. There are also numeracy estimates in the source, they’re also not great for the US ;)
Case refers to the formal markers (in Latin they are endings added to the stem of a noun or adjective) that tell you how a noun or adjective is to be construed in relationship to other words in the sentence. What are the formal markers for English? Here are some reflections on how cases in general relate to meaning in a sentence.