Be careful trying to compare countries or even historical numbers when standards vary. The US has a 99% literacy rate based on some metrics, but as often happens when metrics become useless the people tracking them raise the bar.
Thus the US’s “Level 1” literacy rate, which represents being able to follow basic written instructions, was 92% in 2014. But in 2020 the standard changed yet again to: “54% of adults in the United States have English prose literacy below the 6th-grade level.” Noticeably being literate in a non English language suddenly doesn’t count, the prose at 6th grade level is also higher than it’s been in the past.
Or as Wikipedia puts it: In many nations, the ability to read a simple sentence suffices as literacy, and was the previous standard for the U.S. The definition of literacy has changed greatly; the term is presently defined as the ability to use printed and written information to function in society, to achieve one's goals, and to develop one's knowledge and potential.[3]https://en.wikipedia.org/wiki/Literacy_in_the_United_States
Thus the US’s “Level 1” literacy rate, which represents being able to follow basic written instructions, was 92% in 2014. But in 2020 the standard changed yet again to: “54% of adults in the United States have English prose literacy below the 6th-grade level.” Noticeably being literate in a non English language suddenly doesn’t count, the prose at 6th grade level is also higher than it’s been in the past.
Or as Wikipedia puts it: In many nations, the ability to read a simple sentence suffices as literacy, and was the previous standard for the U.S. The definition of literacy has changed greatly; the term is presently defined as the ability to use printed and written information to function in society, to achieve one's goals, and to develop one's knowledge and potential.[3] https://en.wikipedia.org/wiki/Literacy_in_the_United_States