Audiences returned for HBO’s series finale of “True Blood” on Sunday, with the vampire drama gaining about 500,000 viewers week-to-week and going out with a season high.

According to Nielsen estimates, an average audience of 4.1 million tuned in for the 9 p.m. telecast  — on par with last year’s finale (4.14 million) and a bit above its seventh and final-season opener in June (4.03 million).

Add in a quickie repeat at 11:30 p.m., and the nightly audience for “True Blood” reached 4.5 million. The final season of the show averaged a gross audience of 9.4 million viewers across platforms, according to HBO.

“True Blood” was HBO’s most popular series from 2009 through 2012, peaking with a “live plus same-day” average of 5.16 million viewers during its fourth season, in 2011. Prior to Sunday’s finale, its first nine episodes of the final season had averaged 3.42 million.

For this summer, “True Blood” is television’s second most popular scripted series among young adults, according to Nielsen’s “most current” averages, behind CBS’ “Under the Dome.”

Following the “True Blood” series finale, rookie drama “The Leftovers” drew a series-best 1.9 million viewers. Season-to-date, it is averaging 7.3 million viewers per episode across platforms.