> First, literacy isn't completely related to the writing system. Look at Spanish speaking countries, where the alphabet is more phonetic than the English alphabet.

Perhaps more to the point, Japan, which uses Chinese characters for nouns, adjectives, adverbs, and verb-roots, has a very high literacy rate. [1]*

[1] https://nces.ed.gov/pubs2014/2014008.pdf

* Not trying to cherry-pick for Japan being at the top, but Japan's not listed in the 2015 UNESCO report that's referenced all over the place. This US DoE report from 2013 seems legitimate enough.