Phoenix librarian Rita Hamilton said digital material use makes up about 14 percent of the library system's circulation, which is more than double the amount a year ago.
“Digital materials are never overdue because it’s automatically returned for you, and you can’t destroy it, so there is no replacement fees," she said.
She said there are no plans to increase fines or fees, but they will likely go after more grants. They also make money through room rentals and copy machines.
"The library's not really a revenue generator, free education," she said. "So, it's not really a concern for us."
The Phoenix Public Library includes Burton Barr Central Library and 16 branch locations.