The literacy figure for China would be quite doubtful, as well, and definitely based on a more relaxed standard of "literacy" than in the United States. By official Chinese government survey,
However, all Chinese languages use the same written representation, so any Chinese person speaking a dialect of Chinese that is literate is as literate as a Mandarin-speaker.
This is doubtful as well, because the standard modern written language is based on the vocabulary and grammatical structures of Mandarin. (I am well aware of this, as someone who has lived for years in places where Mandarin is the official language, but the home language of most elementary pupils is a non-Mandarin Sinitic language.) A fairly detailed response to the claim that Chinese characters provide common literacy for people who can't understand one another over the telephone can be found in
India 60.1%
China 90.9%
USA 99%
Seems like by that benchmark, India at least, isn't really competition.