(upi.com) - "Indiana Jones and the Kingdom of the Crystal Skull" is estimated to have earned $151 million at the North American box office since it opened Thursday.The Los Angeles Times said the fourth installment in the franchise is poised to secure the second-best box office take for a Memorial Day weekend opening.The record was set last year by "Pirates of the Caribbean: At World's End," which earned $153 million for the same period of time."Crystal Skull," a 1950s-set adventure film starring Harrison Ford, Karen Allen and Cate Blanchett, grossed $126 million in its first four days of release and was expected to take in another $25 million Monday, the Times said. "For bragging rights, the filmmakers may have wished it would have overtaken 'Pirates,'" media analyst Harold Vogel told the newspaper. "But there's no denying that these are very impressive results."