For the Pew, the study confirms that Americans’ usage of libraries is sliding down in real terms. Last year, in a similar report, the think tank said it was too soon to tell if the apparent downward slide constituted a real trend; now it’s ready to certify it. What’s more, usage of library websites doesn’t seem to be making up for the shift: It’s stayed flat for three years.

To the Pew, the decline in library use is driven by technological change, so the report implicitly recommends that more libraries publicize their non-print services. Ninety percent of U.S. local libraries offer ebook lending, for instance, but 38 percent of Americans either don’t know or don’t think that their local branch does so. What if they did?

But is that really all that’s up here? When it comes to measuring U.S. library use, the Pew surveys aren’t the document of record: that role belongs to reports from the Institute of Museum and Library Services (IMLS), an independent federal agency. Every other year, the IMLS asks librarians in all 50 states about the state of their enterprise. These reports take a long time to create and process, so the most recent data is from financial year 2013.

That document showed a long downward trend in revenues (mostly local government funding) for libraries that began amid the Great Recession:

Public Library Revenue and Costs, 2002 to 2013

Institute of Museum and Library Services

What do revenues have to do with declining use? Possibly everything. In 2012, the IMLS’s yearly report examined whether more people use public libraries after they receive more public investment. In a word, yes:

We found that as investments, such as revenue, staffing, and programs, increased, so did critical use measures, such as visitation and circulation. In the same way, as investments were reduced, mostly in reaction to post-recessionary budgetary reductions, we saw decreases in library use. Another important finding is that even though investments might have declined, any decreases in use did not drop by the same magnitude. People continue to use their local public libraries—for access to books and information and for gathering as a community.

In other words, there’s empirical evidence that usage tracks investment. If libraries receive more public funds, more people use them. And if governments invest less in its libraries (as they have since 2009), fewer people visit—though the drop in visits from disinvestment isn’t as strong as the rise from investment would be.

The correlation between investment and use makes sense. If libraries have more funds, they can have more staff, more classes, more copies of the latest bestseller, and—maybe most importantly—longer hours. Yet at the same time, people are so eager to use the library that they make time to visit even when hours have been shortened and collections have shrunk.