(Bloomberg) -- Love conquers all, at least on bookstore shelves.

Demand for romance novels is booming in the US, with sales of print copies surging 51% to 32.3 million this year through early December, according to NPD Group. The genre is a bright spot for a publishing industry that is on pace to post its first annual decline in units sold in at least five years.

The category’s popularity surged during the pandemic as Americans sought escapism and feel-good stories; just look at Hollywood’s Christmas movie-blitz for proof. Social media helped by igniting the careers of authors such as Colleen Hoover, who had four titles sell more than 1 million copies this year. The industry has also expanded its audience with more contemporary plots from an increasingly diverse set of writers.

“It's very consumable, and it's binge-able,” said Shannon DeVito, the director of books for Barnes & Noble, where romance is among the top five genres in sales. “You're going to have a happy ending nine times out of 10.”

Sales of printed books, which make up more than 85% of the market, got a Covid bump with Americans spending more time at home. And just like Pelotons and disinfectant wipes, the publishing industry’s growth has disappeared as the economy reopened. Units are down 7% so far in 2022 after averaging 9% gains the past two years, according to NPD, which tracks sales at retailers.

But the romance genre is only gaining steam. The category, which has historically made up about 25% of the US fiction market, has a bestseller list dominated by big publishers such as Simon & Schuster, owned by Paramount Global, and Pearson Plc’s Penguin Group. One big reason for the genre’s success is social media, where there is a growing community of accounts dedicated to book reviews and topics, like “books that made me cry.”

On TikTok, #BookTok is approaching 100 billion views. It was the top hashtag in 2022 on the hottest social media platform, where romance had four of the top five books with the most engagement. Barnes & Noble, the country’s largest book chain, jumped on the trend, including using the hashtag on in-store displays and encouraging employees to post their recommendations.

#BookTok serves like a book club at scale, according to Leah Koch, co-owner of the Ripped Bodice, a romance bookstore in Culver City, California. Her store gets dozens of customers coming in each week and asking for titles they heard about on TikTok, she said.

“The rise of TikTok cannot be denied,” said Koch, who called the boom in romance a “cultural shift,” while also pointing out that the genre has had big commercial hits before with franchises such as Twilight and 50 Shades of Grey.

Hoover, who publishes through Simon & Schuster’s Atria division, has been one of the biggest beneficiaries of book content becoming popular on social media. Her title It Ends With Us took off on TikTok in 2020, four years after being released. The book has spent 79 weeks on the New York Times Bestseller list. Its sequel, It Starts With Us, debuted in October and sold 800,000 copies in a week.

The 43-year-old isn’t writing fairytales. She broaches subject matter like abuse and sexual assault. In It Ends With Us, the main character endures intimate partner violence. Such storytelling has helped make Hoover a force with an online following of 3 million combined on Instagram and TikTok. In 2022, Hoover has sold more than 8 million romance books and has the five best-selling titles in the category, according to NPD.

Romance is also getting a little more diverse. According to an analysis by the Ripped Bodice bookstore, 12% of the books published by major romance imprints in 2021 were written by Black, Indigenous and other authors of color. That’s up from a low of 6.2% in 2017.

Yet any strides toward a more diverse bookshelf aren’t necessarily reflected on TikTok, where the majority of breakout books have been by White authors. As a result, the majority of shoppers coming to The Ripped Bodice, which has seen an influx of younger readers, ask for books written by White authors, according to Koch.

“Hopefully, if we're able to get them in the door, then we can introduce them to authors beyond the ones that are trending,” Koch said.

If they do, they have options. Koch touted Alexis Hall’s A Lady for a Duke, which features a transgender heroine, as one of her favorites this year. Jasmine Guillory writes about Black heroines getting their happily ever after. Casey McQuiston weaves LGBTQ romances. They’re all a far from cry from the stereotypical notions about the genre’s typical fare.

“A lot of people still see the Fabio mass-market paperback model,” said Kristen McLean, an analyst for NPD. That’s “their mother’s romance.”

©2022 Bloomberg L.P.