Little, Brown and Company, the publisher of J.K. Rowling's new novel The Casual Vacancy, announced that the book sold 375,000 copies across all formats, print and digital, in its first six days on the market.

How does that compare to other titles?

Harry Potter and the Deathly Hallows, the final book in Rowling's hit series, sold 8.3 million copies in its first day. 

The Fifty Shades of Grey trilogy sold about three million copies its first month in print (it started as an ebook only). 

No Easy Day, the memoir by a former SEAL about the killing of Osama Bin Laden, which had the biggest debut of the year to date, sold 254,000 copies according to Nielsen Bookscan, which tracks about three-quarters of all U.S. print book sales. 

Rowling's book recorded 157,000 sales  through Nielsen's tracking, suggesting print and ebooks are selling at about a 1:1 ratio.

"The Casual Vacancy has exceeded our expectations in its first six days in stores,” said Little, Brown publisher Michael Pietsch in a statement.  “We believe it is on track to become the year's bestselling novel in hardcover."

Pietsch's carefully calibrated statement leaves out Fifty Shades (debuted in paper) and No Easy Day (nonfiction) from the calculation.

The Casual Vacancy is Rowling's first adult novel and her first non-Potter book since publishing the seventh and final volume in the mega-successful series in 2007. 

Her new novel has received mixed reviews with The Wall Street Journal praising it and The New York Times and USA Today panning it.