"Titanic" was No. 1 for a record 15th week as "Grease" failed to slide the box office behemoth out of the top spot, according to industry estimates Sunday.

"Titanic" earned $16 million to boost its North American tally to $516 million - it passed the $500 million mark on Thursday."Grease," another Paramount product, opened with $13 million in receipts, according to Exhibitor Relations Co. Inc. The musical starring Olivia Newton John and John Travolta was digitally remastered for its 20th anniversary re-release.

"The exit polls are great. People are singing and clapping and applauding. It's all ages and demographics," studio spokesman Blaise Noto said.

Travolta also starred in the third-place film "Primary Colors," which grossed $7.3 million in its second week of release.