"The statistics on rate of learning English are impressive."
I came across this sentence in a grammar textbook.
I do not understand why there is not a definite article before for "rate of learning English" since one of the rules for using a definite article is that the noun is restricted to a phrase/clause. In this case, I believe the noun "rate" is restricted by the phrase "of learning English" and the word "rate" is a countable noun, so, if I understand the rules correctly, it should be either in its plural form,"rates"; or with an article prior to the word itself, as in:
"The statistics on rates of learning English are impressive"
"The statistics on the rate of learning English are impressive."
Am I understanding the rules correctly? Or all the 3 example s above are correct and carry similar meanings? Can someone elaborate? Thank you so much.