Bias by Design is an analysis of evolution books reviewed and selected by librarians.
The average number of libraries holding a Not Favorable title is nearly triple than that of libraries having a book supporting Intelligent Design. For nearly every 3 libraries holding a title pooh-poohing Intelligent Design, your patrons will find only 1 library with the temerity to rebut those who find nothing intelligent about Intelligent Design. Availability is certainly no reason for this disparity, pro Intelligent Design books have enjoyed a near 2:1 publication advantage to their counterpart since 2000.
Interesting points here regarding the role of the library.