2M library card holders, which represents about 10% of the number of people who are eligible for a library card, and fewer than 1/2 checked out a book.

So 5% of the total eligible population used one.

Don't get me wrong, I love libraries and I go every week with the kids, but I think OP is right -- few people actually use the library.

> So 5% of the total eligible population used one.

That's not a good metric to use because everyone who lives or works in New York State is eligible to join, but for most people it only really makes sense to join if you live in Manhattan, Brooklyn, or Staten Island. Otherwise you'd just join your local library.

So really ~60% of all residents (i.e. including young children) have a library card, and the overwhelming majority take advantage of library services and events.