LOS ANGELES — Hollywood studios are squeezing more into their weekend box office reports this year, adding ticket sales from Thursday shows and making big movie openings look even more lucrative.

Fourteen films this year with opening-weekend sales of more than $50 million were screened on Thursday nights in U.S. theaters, according to showtimes from Fandango.com, the ticket- buying service. That compares with two last year, when most early showings started at 12:01 a.m. on Friday.

The Thursday shows give studios extra business on a slow night and, in some cases, the chance to trumpet record totals with the extra day tossed in to the traditional Friday-to-Sunday tally. While the new accounting suggests a better reception for a movie, it can muddle comparisons with earlier films.

A recent example is “The Hunger Games: Catching Fire.” While Lions Gate Entertainment Corp. officially released the film on Friday, Nov. 22, theaters across the U.S. began showings at 8 p.m. the night before.

Lions Gate reported that “Catching Fire” generated $158.1 million in opening weekend sales – $5.6 million more than the first “Hunger Games” movie in 2012. The new film’s total was bolstered by $25.3 million in Thursday night screenings, complicating comparisons with the first “Hunger Games,” which didn’t play earlier than midnight.

“We’re entering a new period where you can put an asterisk by opening weekends and say it includes Thursday too,” said Phil Contrino, an analyst with researcher Boxoffice.com.