In updated national estimates from Nielsen, the Grammy Awards on CBS averaged an 8.5 rating in adults 18-49 and 25.3 million viewers overall from 8 to 11:30 p.m. on Sunday — six-year lows in both categories. It was down 14% in the demo and 11% in overall audience from last year.

The only entertainment telecast to rate higher in 18-49 this season was the season premiere of AMC’s “The Walking Dead” in October (8.65 rating). Ratings for last night’s midseason-premiere episode of the drama are expected to be released later today.

In primetime, CBS on Sunday more than doubled NBC, ABC and FOX combined in viewers (20.10 million vs. 9.59 million), adults 25-54 (7.7 vs. 3.4), adults 18-49 (7.0 vs. 2.8) and adults 18-34 (6.1 vs. 2.0).

CBS.com saw record traffic for a Grammy Awards broadcast, with +133% year-over-year growth in unique users to Grammys-related content. Live-streaming of “Grammy Live,” CBS.com and Grammy.com’s multiplatform coverage leading up to and throughout the telecast, generated nearly 7.5 million streams, up more than 40% over the previous year.

In addition, Nielsen Social ranks the “57th Annual Grammy Awards” as the biggest social entertainment program of the 2014-2015 TV season to date, with more than 13.4 million comments on Twitter.

While the Grammys will remain the No. 2-rated awards telecast of the 2014-15 season (behind the Oscars later this month), this year’s event, which saw Sam Smith come away the big winner with four trophies, was down by more than 14% in the demo from last year (9.9/25 in 18-49, 28.51 million viewers overall).

Due to an earlier January air date, last year’s Grammys didn’t have to face AMC’s “The Walking Dead,” which made its midseason return last night, but the music kudocast had faced the zombie drama the prior two years.

Earlier in the 2014-15 season, adults 18-49 ratings were also  lower for the CMA Awards on ABC (down 4%, 4.5 vs. 4.7), the American Music Awards on ABC (down 16%, 3.8 vs. 4.5) and the Golden Globe Awards on NBC (down 11%, 5.8 vs. 6.5).

CBS dominated Grammy night as usual, with the awards show more than tripling its combined ABC-NBC-Fox competition from 8 to 11 p.m. (8.8 vs. 2.9 in 18-49 and 26.2 million vs. 8.3 million).

“60 Minutes” was the night’s No. 1 series broadcast (1.5/5 in 18-49, 9.9 million viewers overall), while AMC’s “The Walking Dead,” ratings for which will be issued later today, is expected to rule as Sunday’s No. 1 series overall.

ABC ran second to CBS among the broadcasters with an original “America’s Funniest Home Videos” (1.4/4 in 18-49, 6.6 million viewers overall) and the network television premiere of “The Hunger Games” (1.1/3 in 18-49, 3.5 million viewers overall).

Fox aired original episodes of its Sunday comedies “Mulaney” (0.5/2 in 18-49, 1.2 million viewers overall), “The Simpsons” (1.2/3 in 18-49, 2.8 million viewers overall), “Brooklyn Nine-Nine” (1.2/3 in 18-49, 2.6 million viewers overall), “Family Guy” (1.4/3 in 18-49, 2.7 million viewers overall) and “Bob’s Burgers” (1.0/2 in 18-49, 1.9 million viewers overall).

Preliminary 18-49 averages for the night: CBS, 7.0/19; ABC, 1.1/3; Fox, 1.0/3; Univision, 0.8/2; NBC, 0.7/2; Telemundo, 0.3/1.

In total viewers: CBS, 22.1 million; ABC, 4.2 million; NBC, 3.2 million; Fox and Univision, 2.2 million; Telemundo, 0.7 million.