Bloomsday is celebrated annually on June 16 in honor of James Joyce’s 700+ page epic novel Ulysses. Why this day? It’s the anniversary of the date in 1904 when all of the book’s “action”–tracing the steps of protagonist Leopold Bloom on an ordinary day in Dublin–takes place. Modern Library ranks Ulysses as the 20th century’s best novel, and TIME categorizes it as the most influential novel of the century. So it’s not surprising that the book gets its own special day of devotion, which includes 12K runs, literary festivals, and lots of Guinness and public readings of the novel. What’s somewhat surprising given all of the book’s adulations, however, is how shockingly common it is for even people who own Ulysses to have never read it, at least not in its entirety. James Latham, editor of the University of Tulsa-based James Joyce Quarterly, recently described Ulysses as probably “the most purchased and least read book in the world,” according to the Tulsa World. Just how accurate is that description? We wanted to find out, if for no other reason than to ease the sheepishness some of us feel for not having read Ulysses. (I have only read Portrait of the Artist as a Young Man and “The Dead.”) You may have always suspected that your friend with the full collection of Penguin Classics was using those books primarily as interior decoration. This is fine, of course: The publishing industry needs all the help it can get—and Umberto Eco says a library filled with unread books is far more valuable. Data suggests that many people indeed buy the works of Joyce and other high-brow literary authors for largely the same reason that Hansel from “Zoolander” admires Sting: Sting would be another person who’s a hero. The music he’s created over the years, I don’t really listen to it, but the fact that he’s making it, I respect that. Since detailed data and metrics have supplanting sales and subscriptions in publishing, the world of media has changed significantly to focus on what people read. As Vox’s Todd VanDerWerff put it last year, “Newspapers could suspect nobody was reading the city council report or the dance review; with the internet, we know nobody is.” For books, however, data has been less forthcoming since most people cling to their metric-proof bits of wood pulp, thread, and glue. But not completely. Thanks to the Kindle and other e-readers, there is some data showing who has actually been reading. Amazon’s devices communicate and sync with each other, through the company, revealing how many people downloaded a book, whether they read it, and how long it took. Unfortunately, Amazon rarely (like never) shares its data. But there are other ways of telling whether your pedantic friend has actually made it through the Great Slogs—and I say this with love to the great books, many of which I have read. (Or have I?) In 2014, University of Wisconsin-Madison Professor Jordan Ellenberg invented the so-called “Hawking Index,” which uses Amazon e-book highlights data as a proxy for where people stop reading the books they’ve purchased. Some people use the highlight function on the devices and apps, and the unscientific-but-workable “Hawking Index” uses the assumption that if the most-highlighted passages are clustered at the beginning of the book, the book is more likely to have been abandoned. (The name refers to Stephen Hawking’s A Brief History of Time, which is ranked up with Ulysses for the dubious title of “most unread book of all time.”) On the other side, books with popular passages marked all the way to the end mean lots of people made it through the entire story. Read Next: The Only Two Investing Books You Really Need to Read So on this Bloomsday where does Ulysses truly stack up? Here’s a list of famous books and their scores on the Hawking Index, ranked from most-likely abandoned to most likely-finished. Book Author HI Score Ulysses James Joyce 1.7% Les Miserables Victor Hugo 1.8% Capital in the Twenty-First Century Thomas Piketty 2.4% Hard Choices Hillary Clinton 4.2% A Brief History of Time Stephen Hawking 6.6% Thinking Fast and Slow Daniel Kahneman 6.8% Lean In Sheryl Sandberg 12.3% Infinite Jest David Foster Wallace 15.0% Moby Dick Herman Melville 19.2% Art of the Deal Donald Trump 19.4% Time to Get Tough Donald Trump 19.6% A Tale of Two Cities Charles Dickens 21.3% Flash Boys Michael Lewis 21.7% Between the World and Me Ta-Nehisi Coats 23.9% Fifty Shades of Grey E.L. James 25.9% The Great Gatsby F. Scott Fitzgerald 28.3% Portrait of the Artist as a Young Man James Joyce 29.6% Catching Fire Suzanne Collins 43.5% Harry Potter and the Sorcerer’s stone J.K. Rowling 95.9% The Goldfinch Donna Tartt 98.5% So, as you can see, if you abandoned Ulysses, you’re hardly alone. Likewise, if you didn’t quite make it through A Brief History of Time, which you maybe thought was brief and readable since it is just over 250 pages, let that weight off your shoulders. If Hillary Clinton’s Hard Choices really didn’t work for you, don’t worry: No one else read it in its entirety either. Unfortunately, you can only evaluate a book on this scale if you have purchased it. The above list isn’t comprehensive since it is limited to 20 I could access. If you’re curious about how abandoned a book is, buy the Kindle edition, find the popular highlights page, sort by popularity, and average the page numbers of the five most popular. Divide by the number of pages (or locations—Amazon sometimes uses this bizarre digital waypoint) and you have your score. The company of quitters might make you feel less guilty. If you still feel guilty about not reading Ulysses, well, today’s the best day of the year to give it yet another try. It’s a great book (or so we hear). Happy Bloomsday!