Fifty Shades of Grey trilogy just set another record: It has sold over 100 million copies as of this week.

Vintage Books told the New York Times that the three books in the series by E.L. James have hit a number that has only been reached by popular series like Harry Potter, Twilight, and the Nancy Drew books. The news is particularly interesting given Fifty Shades started as a Twilight fan fiction.

Fifty Shades saw their strongest sales in 2012 when word of mouth and its presence in pop culture was most rampant for the romantic series.

The NYT notes that booksellers have not seen sales increase for other books that tell similar stories, suggesting readers have been visiting the Fifty Shades genre for only a brief period of time before going back to their usual reading.

Fifty Shades of Grey’s milestone comes as the film adaptation wraps filming in Vancouver. The movie’s official Twitter account noted they finished filming by sharing a picture of James and director Sam Taylor-Johnson celebrating on set:

Fifty Shades of Grey will open in theaters Valentine’s Day weekend 2015, just in time for those who are looking for a romantic movie to celebrate the holiday.

The film stars Dakota Johnson as Anatasia Steele and Jamie Dornan as Christian Grey. Supporting actors include Jennifer Ehle, Marcia Gay Harden, Rita Ora, and Luke Grimes. The first poster was released in January and has been appearing in major cities around the United States. A still released on Valentine’s Day earlier this month depicts Anastasia laying eyes on Christian for the first time.

Thanks, NYT.