Why Literacy "Rate"?
Literacy refers to the quality or state of being literate, esp. the ability to read and write. Literacy rate refers to the percentage of people who are able to read and write vs those who are not.
Literacy:
- The condition or quality of being literate, especially the ability to read and write
Literacy rate
- (social studies) the percentage of people who are able to read and write
Rate:
- A measure of a part with respect to a whole; a proportion: the mortality rate; a tax rate.
( TFD)
Ngram : literacy rate, ratio, proportion, percentage.