Total domination: 'Fifty Shades of Grey' scores at US box office

Steamy bondage romp "Fifty Shades of Grey" dominated at the North American box office this weekend, whipping the competition to secure top spot, industry estimates showed Sunday.

The erotic tale of billionaire Christian Grey (Jamie Dornan) and his sadomasochistic relationship with college graduate Anastasia Steele (Dakota Johnson) pulled in $81.7 million -- more than 40 percent of all ticket sales -- over its opening weekend, according to preliminary numbers from box office tracker Exhibitor Relations.

Another Valentine's Day weekend opener was British spy-comedy flick "Kingsman: The Secret Service," starring Colin Firth and Samuel L. Jackson, which debuted in second place with a haul of $35.6 million.

The performance of the two newcomers was easily enough to shove last week's top film, "The SpongeBob Movie: Sponge Out of Water," down to third place, with $30.5 million in sales.

"American Sniper," relegated to fourth place, had $16.4 million in ticket sales.

Since its release, the highly acclaimed "Sniper" has raked in $304 million and a half-dozen Oscar nominations, including a best actor nod for Bradley Cooper in the title role.

"Jupiter Ascending" sold the fifth most tickets, with a $9.4 million in its second weekend.

The fantasy flick pairs Mila Kunis and Channing Tatum and is a first foray into the genre for sibling directors Lana and Andy Wachowski since their work on "The Matrix" series.

"Seventh Son," a 3-D fantasy-action film starring Jeff Bridges and Julianne Moore, was in sixth place, earning $4.2 million.

"Paddington," a big-screen adaptation of the family classic about a bear lost in the big city, earned $4.1 million for the seventh spot.

Comedy "The Wedding Ringer" took $3.8 million in eighth place, followed by "The Imitation Game," which stars Benedict Cumberbatch as codebreaking genius Alan Turing, with $3.5 million in ninth.

Rounding out the top 10 was "Black or White," a racially charged drama starring Kevin Costner as a widowed grandfather battling to retain custody of his mixed-race granddaughter, with $3.3 million.