On Friday, the mayor’s office in Monroeville, Alabama, announced that Harper Lee, author of the 1960 Pulitzer Prize-winning novel “To Kill a Mockingbird” and its controversy-plagued 2015 sequel “Go Set A Watchman,” had died at age 89. A look at the numbers behind Lee’s greatest work bear out its prominent place in American culture.

In 2012, the Fordham Institute, an education policy think tank, surveyed 484 high school English teachers about which books they assigned. According to the group’s study, “Mockingbird” was taught by more ninth- and 10th-grade teachers — 35 percent of them — than any other book of fiction listed. It also tops most works in other categories, including poetry and plays. “Mockingbird” beats the most-taught works of Mark Twain, Shakespeare or John Steinbeck. The only reading material that topped it was Martin Luther King Jr.’s “I Have A Dream” speech, which was taught by 38 percent of teachers in those grades.

The book is also widely taught on college campuses. According to the Open Syllabus Project, which tracks books that are listed on more than a million college syllabi nationwide, “To Kill a Mockingbird” was assigned 633 times, making it the 255th-most-assigned book in the database — an impressive rank, considering that the vast majority of the titles are either textbooks or predate the 20th century. (Of the top 10 books, only two — E.B. White and William Strunk Jr.’s “The Elements of Style” and Neil Campbell’s textbook “Biology” — were published after 1850.)

In terms of determining where “To Kill a Mockingbird” stands among similar texts, the Open Syllabus Project also has data on which books are the most likely to be assigned together in college, which could be a somewhat more useful proxy for comparing books that contributed to American culture in the same way. “To Kill a Mockingbird” was most likely to be assigned along with J.D. Salinger’s “The Catcher in the Rye,” William Golding’s “Lord of the Flies,” F. Scott Fitzgerald’s “The Great Gatsby” and George Orwell’s “Animal Farm.”

To get a sense of how popular these books are beyond college classrooms, Goodreads is the place to go. Of the five books listed above, “To Kill a Mockingbird” has both the highest number of ratings and the highest average rating, 4.23 out of 5 stars.

But even though there’s a pretty established consensus that it’s a great book (though there are dissenting opinions), Google search data shows that we probably can’t separate it — or any of the books associated with it — from the classroom.

The seasonality of the search data hints at the link between the books’ popularity and their use in the classroom. Most searches for the five books take place around May every year, presumably when students are studying for finals or writing essays. There’s also a similar, albeit smaller, uptick around November or December every year — another indicator of cramming for midterms or finals.

The May 2013 spike in searches for “The Great Gatsby” is no doubt tied to the release of Baz Luhrmann’s film adaptation. But even with that factored in, “To Kill a Mockingbird” still wins the search game over time; until 2012, Lee’s novel was the most-searched of the five, and on average since 2004, it’s still been searched about 10 percent more often than Fitzgerald’s.

The data on Lee’s influence is clear, but it really just tells us what we already know: By grappling with racial injustice in American society — an issue that we still struggle with — Harper Lee’s work endures, and will continue to do so for many years to come.