Broadway box office held rock-steady last week, with declines at some shows balanced by rises at others in what was a healthy summertime frame overall.Among the most notable productions to rise was “A Streetcar Named Desire” ($616,897), which capped off its run of generally middling sales with a hefty spike, shooting up 26% (or $125,000) in its final week on the boards. The spring season’s hot-ticket musicals, “Once” ($1,069,942) and “Newsies” ($1,066,049), also gained some steam, with “Newsies” breaking the house record at the Nederlander Theater for the fifth time. Other significant increases were logged at two plays, “Harvey” ($666,018) and “The Best Man” ($621,505), each buoyed by familiar faces in the cast such as Jim Parsons at “Harvey” and Cybill Shepherd and John Stamos in “Best Man.” “The Phantom of the Opera” ($1,022,487), always popular with city visitors thanks to the title’s high global profile, also climbed — as did “The Lion King” ($2,219,534) and “Wicked” ($2,145,917), which each played an extra, ninth perf last week and walked away with an additional chunk of change to show for it. Increases such as those balanced out the slowdowns at other productions. Biggest drop of the sesh was at “Evita” ($1,039,330), slipping due to the three sick-day absences taken by topliner Ricky Martin but still proving robust enough to land in the millionaires’ club. “Nice Work If You Can Get It” ($767,559), “Ghost” ($528,401) and “Clybourne Park” ($358,048) also slackened. Despite that, overall sales upticked slightly to $23.8 million for 28 shows on the boards. Attendance, too, remained essentially flat, holding steady at 239,2723. One of the newest additions to the Main Stem slate, “Bring It On” ($374,495), played its first frame of seven previews vs. the four it played the prior week. It’s too early to tell whether the show will continue to gain momentum, although execs involved in the production have said daily ticket sales are on the rise. Also up last week was the temporary return of “Fela!” ($305,190), but its low-end numbers point to the marketing challenge posed by the last-minute scheduling of the musical’s summertime stint in Gotham.