This overall structure of this sentence is: The quantity of X numbers in the many thousands. X is a long noun phrase. "numbers" is a verb.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
This overall structure of this sentence is:
The quantity of X numbers in the many thousands.
X is a long noun phrase. "numbers" is a verb. The subject of "numbers" is "the quantity of X". The sentence is basically saying that there are many thousands of X (i.e. many thousands of books, newspapers etc. were read).