Americans have objected to titles as diverse as the Bible and Fifty Shades of Grey over the last year, according to a list of the most challenged books which has just been released by the American Library Association.

The Bible made the line-up for 2015 in sixth place, the ALA said, with users objecting to its presence in libraries and schools over its “religious viewpoint”. The text has not previously appeared in the ALA’s annual citation of challenged titles.

Sometimes it’s retaliatory action... a religious group objects to a book and a parent responds by objecting to the Bible James La Rue, ALA Office for Intellectual Freedom

James La Rue, director of the ALA’s Office for Intellectual Freedom, speculated to Associated Press that its inclusion was down to “people who feel that if a school library buys a copy of the Bible, it’s a violation of church and state”.

“And sometimes there’s a retaliatory action, where a religious group has objected to a book and a parent might respond by objecting to the Bible,” said LaRue.

The book to receive the greatest numbers of challenges in 2015 was John Green’s young adult novel Looking for Alaska, said the ALA, with objections raised over its “offensive language”, “sexually explicit” scenes and suitability for the age group. The novel is the bestselling author of The Fault in Our Stars’ debut, and tells of Miles Halter and how he falls for Alaska Young. “If people were rain, I was drizzle and she was a hurricane,” he writes.

EL James’ erotic novel Fifty Shades of Grey came in second, drawing criticism for being “sexually explicit”, “poorly written” and even over “concerns that a group of teenagers will want to try it”.

Transgender picture book I Am Jazz was in third, with a collection of interviews with transgender teenagers, Beyond Magenta, in fourth. The ALA’s Office for Intellectual Freedom defines a challenge as “a formal, written complaint, filed with a library or school requesting that materials be removed because of content or appropriateness”.

Mark Haddon’s novel The Curious Incident of the Dog in the Night-Time was in fifth place; last summer, the title was pulled from a Florida school’s summer reading list after parents objected to the swearing contained in the text. Haddon said at the time that the book was “not just a novel which contains swearing but a novel about swearing”. Its main character, Christopher, a 15-year-old with Asperger syndrome, “is completely unaware of the offence that swearing is intended to cause and therefore it simply washes over him,” said Haddon, adding that “no-one has ever complained that the book is about a mother abandoning her son or that it contains a scene in which a father hits his son … But many people have complained that it contains the word ‘cunt’.”

Other titles on the list include Alison Bechdel’s acclaimed graphic memoir Fun Home, and David Levithan’s novel Two Boys Kissing. In total, 275 challenges were recorded by the ALA’s Office for Intellectual Freedom, down from 311 last year, and 464 in 2012. But the library body estimates that for every reported challenge, four or five remain unreported, and that “censorship is still a very serious problem”.

Over the last decade, it said it received reports of over 5,000 challenges to books, with “sexually explicit” material cited the most often (1,577 times) as a reason for an objection. The “vast majority” of challenges were initiated by parents (2,535), said the ALA.

Top 10 most challenged books of 2015:

1. Looking for Alaska by John Green

2. Fifty Shades of Grey by EL James

3. I Am Jazz by Jessica Herthel and Jazz Jennings

4. Beyond Magenta: Transgender Teens Speak Out by Susan Kuklin

5. The Curious Incident of the Dog in the Night-Time by Mark Haddon

6. The Holy Bible

7. Fun Home by Alison Bechdel

8. Habibi by Craig Thompson

9. Nasreen’s Secret School: A True Story from Afghanistan by Jeanette Winter

10. Two Boys Kissing by David Levithan