"Transformers: Age of Extinction" held on to the top spot at the North American box office with an $36.4 million during what proved to be a lackluster Fourth of July weekend.

That brought the film's North American total to $174.7 million -- which is enough to make it the seventh highest-grossing film of the year in just two weeks.

Worldwide the fourth "Transformers" film has earned $575.6 million thus far, with about $400 million of that coming from overseas. The film has now made $212.8 million in China, where it is the No. 2 top-grossing film of all time. China's No. 1 film of all time, "Avatar," made $221.9 million over the course of its lifetime.

Looking at the rest of the North American box office, "Tammy," the new comedy starring Melissa McCarthy, came in second with an estimated $21.1 million. It was followed by another opener, the horror film "Deliver Us From Evil," which made an estimated $9.5 million. "22 Jump Street," with an estimated $9.4 million, and "How to Train Your Dragon 2," with an estimated $8.7 million, rounded out the top five.

The Korean film "Snowpiercer," based on the French graphic novel "Le Transperceneige" by Jacques Lob, Benjamin Legrand and Jean-Marc Rochette, expanded from eight locations domestically to 250 in its second week. The film made an estimated $999,000 this weekend, bringing its total to $1.5 million.

According to Variety, the total North American box office take this weekend was around $122 million -- "the lowest Independence Day box office in at least a decade" -- compared to $230 million a year ago. The trade notes that last year the Fourth of July fell on a Thursday, which it says encouraged more mid-week trips to the movies. Last year "Despicable Me 2″ made $143 million over the longer holiday weekend, while "The Lone Ranger" opened to $48 million.

So far the 2014 summer box office is down about 20 percent compared to last year. But with "Dawn of the Planet of the Apes" and "Guardians of the Galaxy" on the horizon, things could still turn around.