AMC’s “Mad Men” has never been a ratings juggernaut, but even by its standards it returned to modest numbers Sunday night.

According to Nielsen, Sunday’s seventh-season opener averaged about 2.3 million — well below its year-ago opener of 3.37 million and also lower than its June season finale of last year (2.69 million).

In the adults 18-49 demo, last night’s premiere averaged a 0.8 rating (about 1 million viewers), down from the 1.14 rating for its year-ago premiere and the 0.85 for its year-ago finale.

The 12 episodes of last year’s sixth season of “Mad Men” averaged a 0.9 rating in adults 18-49 and 2.65 million total viewers in same-night numbers. And in Live+7, it rose to a 1.6 in the demo and 3.94 million viewers overall.

“Mad Men’s” ratings peak to date was its fifth-season premiere in March 2012 — the first episode of the show in 17 months — which drew 3.54 million and a 1.2 rating in adults 18-49.

Though it draws a relatively small audience, “Mad Men” is the most upscale-skewing show on ad-supported television in adults 18-49, according to Nielsen. AMC also notes that Sunday’s premiere is currently the No. 1 television show on iTunes, and the show is the No. 1 season pass on iTunes.

Leading into “Mad Men” on Sunday, the second episode of “Turn” averaged about 1.9 million viewers.