NBC’s “America’s Got Talent” dominated Tuesday’s primetime ratings action despite a week-to-week dip, while CBS’ “Zoo” — summer’s most-watched new scripted series — held steady. Over at Fox, meanwhile, new feel-good alternative series “Knock Knock Live” made very little noise in its bow.

According to preliminary national estimates from Nielsen, “America’s Got Talent” averaged a 2.3 rating/9 share in adults 18-49 and 10.3 million viewers overall from 8 to 10 p.m., at the low end of its ratings range this summer but still strong enough to out-rate the combined demo delivery of ABC, CBS and Fox (2.1) during its time period. The Peacock stayed on top at 10 p.m. with “Hollywood Game Night” (1.3/5 in 18-49, 4.9 million viewers overall), down a tick from last week.

With “Talent” and “Game Night” the top two shows of the night in 18-49, NBC won with ease. It also finished on top in adults 25-54 and total viewers.

At CBS, encores of “NCIS” (0.8/3 in 18-49, 7.5 million viewers overall) and “NCIS: New Orleans” (0.8/3 in 18-49, 5.5 million viewers overall) sandwiched the fourth episode of “Zoo” (1.0/4 in 18-49, 6.6 million viewers overall), which was on par with last week in all key categories. The drama based on the James Patterson novel of the same name is summer’s No. 1 new series in adults 25-54 and total viewers.

Elsewhere, Fox aired an hourlong tenth-anniversary special of “So You Think You Can Dance” (0.8/3 in 18-49, 2.4 million viewers overall), which came in a little below what the show has been averaging on Monday’s this summer (1.1 in 18-49, 3.65 million viewers overall). It was followed by the Ryan Seacrest-hosted “Knock Knock Live” (0.5/2 in 18-49, 1.7 million viewers overall), which drew the smallest demo rating for any Big Four series premiere this summer. The net did the same 0.5 rating with a repeat of “Bullseye” two weeks ago.

ABC had a very quiet night, generating the same low 0.6 rating in 18-49 for repeats of “Fresh Off the Boat” (2.7 million viewers overall) and “Black-ish” (0.6/2 in 18-49, 2.2 million viewers overall) as well as its original two-hour “Extreme Weight Loss” (2.3 million viewers overall). After rallying a bit last week (0.8/3 in 18-49, 2.67 million viewers overall), the weight loss series matched its series low of two weeks ago.

CW aired repeats of “The Flash” (0.4/2 in 18-49, 1.4 million viewers overall) and “iZombie” (0.3/1 in 18-49, 1.1 million viewers overall).

Preliminary 18-49 averages for the night: NBC, 1.9/7; CBS, 0.9/3; Telemundo, 0.8/3; Univision, 0.7/3; ABC and Fox, 0.6/2; CW, 0.3/1.

In total viewers: NBC, 8.5 million; CBS, 6.5 million; ABC, 2.3 million; Fox, 2.1 million; Univision, 1.9 million; CW, 1.2 million; Telemundo, 1.1 million.

    TV Ratings Tuesday, July 21, 2015
    18-49 ratings/share
  1. 1.

    America’s Got Talent

    (8:00 NBC)

    10.3 Million Viewers
  2. 2.

    Hollywood Game Night

    (10:00 NBC)

    4.9 Million Viewers
  3. 3.


    (9:00 CBS)

    6.6 Million Viewers
  4. 4.


    (8:00 CBS)

    7.5 Million Viewers
  5. 5.

    NCIS: New Orleans-r

    (10:00 CBS)

    5.5 Million Viewers