More than 67 million people watched the first presidential debate of this election cycle — nearly 15 million more than watched the first presidential debate four years ago.

That 67 million, however, falls very short of the Mother of All Presidential Debates: the Oct. 28, 1980, smackdown between President Jimmy Carter and Ronald “There You Go, Again” Reagan, which drew a whopping 81 million viewers.

About 12 million of the 67 mil who watched President Obama square off against GOP presidential nominee Mitt Romney on Wednesday evening at the University of Denver were ages 18 to 34, and nearly 31 million of them were 55 years or older, Nielsen reported Thursday.

The debate was carried live across 11 networks; Telemundo aired it on tape-delay.

In a tight race at the top, ABC appears to have snagged the most viewers for the election cycle’s first presidential debate — as it did four years ago. About 11.25 million people watched Romney vow to axe Big Bird (and PBS funding) on ABC.

That’s up a tick from four years ago, when 11 million people watched Sens. John McCain and Barack Obama in their first face-off, which — like Wednesday’s debate — was moderated by PBS’s Jim Lehrer. Lehrer got better reviews in ’08.

This time, ABC was closely followed by NBC, which had about 11.1 million viewers — up a lot from its 7.1 million of four years ago.

CBS snagged 10.6 million viewers, compared with 7.6 million in 2008.

Fox News Channel averaged 10.436 million viewers — also a big improvement over 8.2 million four years ago. CNN clocked about 6.1 million viewers — a 1 million viewer drop from ’08 but still strong enough to beat MSNBC’s average of 4.7 million.

MSNBC showed growth, however, having averaged 3.9 million for the first presidential debate of 2008. But not as much growth as the Fox broadcast network, which is not known for carrying news programming of any kind. (Fox’s debate coverage was anchored by Shep Smith, who had also anchored its coverage in ’08.)

This time, Fox scored nearly 7 million viewers — almost 3 million better than four years back. Notice how the Fox broadcast network — home of “New Girl,” “Family Guy” and “X Factor” — beat cable news networks MSNBC and CNN?

Carey vs. Minaj 2.0

Mariah Carey says she has hired extra security and “doesn’t feel comfortable” at the “American Idol” auditions after show staffers told her that fellow judge Nicki Minaj muttered, “If I had a gun, I would shoot the [woman],” after the two divas argued, Barbara Walters reports.

Just when you didn’t think this melodrama/stunt between the two music stars, who’ve been hired to jack up the ratings on Fox’s singing competition series, couldn’t get any better, in steps Babs and “The View.”

“Nicki is unpredictable, and Mariah says she can’t take a chance,” Walters — the sometime ABC News personality, sometime “The View” den mother — said during the Hot Topics portion of “The View.”

It all started overnight Tuesday when the celebrity suck-up site TMZ published leaked video from the Fox singing competition’s Tuesday auditions in Charlotte. Minaj and Carey are seen exchanging heated words after disagreeing about an auditioner’s performance.