(Credit: Ron Phillips/Warner Bros.)

While blockbusters like "The Avengers" and "The Dark Knight Rises" brought in record sized audiences, this summer may be seeing lower attendance levels than last year, in part due to the shootings in Aurora, Colo., the Hollywood Reporter said.

According to preliminary estimates, there were 533.5 million tickets sold this summer domestically, down 4 percent from last year. The lowest attendance came two summers ago, with 534.4 tickets sold.

Marvel and Disney's "The Avengers" broke box office opening weekend records with about $200.4 million grossed in its opening on May 4.

People are still seeing the film around the world, which completed Labor Day weekend with a worldwide gross of $1.5 billion, the Hollywood Reported said.

The Hollywood Reporter said "Dark Knight Rises" and a number of family films took a hit after the shooting in Auorora, Colo. At a midnight showing of the film on July 20, accused shooter James Holmes killed 12 people and injured 58 in a movie theater.

Still, "Dark Knight Rises" earned $433.2 million through Labor Day weekend domestically, which is a strong figure but significantly less than what the previous Batman film, "Dark Knight" earned: $533.2 million.

The film has had strong overseas earnings, grossing over $1 billion worldwide through Sunday.