When it opened in London in 1999, Mamma Mia was considered a small “filler” show. But it’s become a huge hit. “Currently generating more than $8 million a week in ticket sales, “Mamma Mia!” has grossed more than $750 million worldwide, including $200 million on the West End and $150 million in New York. If the current box office activity continues, the show should easily pass the billion-dollar mark set by “The Phantom of the Opera.”Mamma Mia!” has yet to open in a city or country where it hasn’t clicked, whether you’re talking Korea, the Netherlands, or Australia. The show claims to have been seen by almost one in every 10 Australians.”