Watching a film adaptation of your favorite book is a risky business. At best, you might walk away feeling entertained but slightly disappointed that certain characters or scenes didn’t make it into the movie. At worst, you could end up livid that filmmakers somehow got everything so wrong. Considering Hollywood’s eagerness to adapt practically every book for the silver screen, most avid readers have experienced both scenarios. But which blockbusters have fallen especially short of the mark?

Online retailer OnBuy.com crunched some numbers to find out. This study focused on recent bestsellers, so you won’t find any Jane Austen or Charles Dickens titles in the results. After compiling a list of books with movie adaptations, researchers calculated the discrepancy between each book’s Goodreads ratings and its corresponding movie’s IMDb ratings (both user scores and Metacritic scores). The discrepancies were converted into percentage values and ranked in order of greatest to least.

Since the movies weren’t specifically rated by people who had also read the book, the study isn’t a reflection of how book fans in particular felt about the film version. But it does show which highly anticipated blockbusters were somewhat of a letdown—and according to this list, it was Fifty Shades of Grey that ran away with that dubious honor. There’s a 44 percent discrepancy between ratings for E.L. James’s explosively successful romance novel and the 2015 movie adaptation starring Dakota Johnson and Jamie Dornan.

The second place finisher also debuted in 2015; The Hunger Games: Mockingjay - Part 2, the final film in The Hunger Games series, was rated 19 percent lower than its source material. Right behind it was another franchise finale: 2011’s Harry Potter and the Deathly Hallows: Part 2, tied with the 2016 thriller The Girl on the Train.

The study didn’t only reveal the disappointments. David Fincher’s 2014 take on Gillian Flynn’s Gone Girl, for example, was rated a single percent lower than the book. And the 2009 Swedish screen adaptation of Stieg Larsson’s The Girl With the Dragon Tattoo registered just a 6 percent discrepancy.

Is your least favorite film adaptation here?OnBuy

Peruse the bottom 10 below:

  1. Fifty Shades of Grey (2015) // -44 percent
  1. The Hunger Games: Mockingjay - Part 2 (2015) // -19 percent
  1. The Girl on the Train (2016) // -17 percent
  1. Harry Potter and the Deathly Hallows: Part 2 (2011) // -17 percent
  1. The Da Vinci Code (2006) // -15 percent
  1. The Book Thief (2013) // -13 percent
  1. Me Before You (2016) // -13 percent
  1. The Kite Runner (2007) // -12 percent
  1. The Lovely Bones (2009) // -12 percent
  1. The Help (2011) // -10 percent

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