Margin of error of 1/22/2013 report: +/- 2.3%
Margin of error of 12/11/2013 report: +/- 1.5%
From the 12/11/2013 report on Public library use and library website use: Recent library visitors are more likely to be
- those under age 65,
- adults who have college degrees, and
- adults who live in households earning $100,000 or more.
As for Wisconsin......
The number of (onsite) annual visits to Wisconsin public libraries peaked in 2009 at 35,781,390. Since then the number of visits has declined 6% to 33,627,277.
Pew Research Center Report: How Americans Value Public Libraries in Their Communities. (12/11/2013)