https://en.wikipedia.org/wiki/Literacy_in_the_United_States
"The 15% figure for full literacy, equivalent to a university undergraduate level, is consistent with the notion that the "average" American reads at a 7th or 8th grade level which is also consistent with recommendations, guidelines, and norms of readability for medication directions, product information, and popular fiction." His base. i.e., you mean Americans?
It is claimed that Trump is a moron... maybe, just maybe, he knows his audience The reason he has gotten this far is in large part due to the dismissive attitude of those who deem themselves superior (culturally, morally etc.). Trump is not responsible for the huge US prison population, gun deaths, ongoing racial segregation of the school system, 10-15m immigrants living in legal purgatory, the destruction of the middle class etc. etc. But ya, let's all focus on Trump because then we don't have to look in the mirror.