The American Library Association announced Thursday that the number of books challenged in libraries across the U.S. spiked 65% in 2023 over the previous year, reaching the highest level ever documented by the nonprofit organization.

In a new report, the association says that 4,240 individual book titles were targeted for removal from schools and public libraries — a sharp increase from the previous high of 2,571 in 2022.

The library association, which has monitored attempted book bans since 1990, compiles data on challenges from two sources: reports from library professionals and news stories. The association said the 2023 data “represents only a snapshot of book censorship,” partly because many attempts to challenge books are not formally flagged or covered by the news media.

“The reports from librarians and educators in the field make it clear that the organized campaigns to ban books aren’t over, and that we must all stand together to preserve our right to choose what we read,” said Deborah Caldwell-Stone, director of the association’s Office for Intellectual Freedom.

In recent years, school districts and state legislatures nationwide have been roiled by fierce, politicized debates over what reading materials are appropriate for kids and teenagers. The efforts to restrict or withdraw books have been driven in part by conservative activist groups such as Moms for Liberty as well as Republican politicians.

Meanwhile, lawmakers in at least 13 states this year alone have introduced legislation that could disrupt libraries’ services and censor their materials, according to an NBC News tally.

The American Library Association’s report found that nearly half of the book titles targeted for censorship dealt with “the voices and lived experiences” of the LGBTQ+ community and people of color. 

In 2022, the library association’s list of the 13 most challenged books nationwide included Maia Kobabe’s “Gender Queer: A Memoir,” George M. Johnson’s “All Boys Aren’t Blue,” Toni Morrison’s “The Bluest Eye” and Juno Dawson’s “This Book Is Gay.” (The association plans to announce the list of the 10 most challenged books of 2023 on April 8.)

The library association’s report illustrates that challenges to books have grown more concerted and aggressive. The report’s authors learned that people are “demanding the censorship of multiple titles, often dozens or hundreds at a time.” 

More than 2,670 titles were challenged in Florida last year, according to the association’s data. The report logged efforts to censor more than 100 titles in 16 other states, including Illinois, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, Utah and Wisconsin.

“Each demand to ban a book is a demand to deny each person’s constitutionally protected right to choose and read books that raise important issues and lift up the voices of those who are often silenced,” Caldwell-Stone said in a statement.

The issue has drawn increased national attention over the last year as speech advocates, educators, parents and progressive activists raise alarms. “The ABCs of Book Banning,” a documentary short directed by former HBO executive Sheila Nevins, received an Oscar nomination this year.