From the OverDrive blog:
OverDrive conducted an end user survey from June 26-July 15, 2015. Administered via library websites, the survey collected input from 16,756 respondents. Their full report examines the positive effect the shift to digital content has had on the role of libraries in their communities by helping attract new readers, serve existing patrons better and reach beyond their physical walls.
There is a nice infographic on the original OverDrive blog post.