Friday, May 31, 2013 ratings — Premieres: Primetime: What Would You Do?. New episodes: 20/20, Dateline, and Rock Center With Brian Williams. Reruns: Bones, The Following, Shark Tank, Undercover Boss, Hawaii Five-0, Blue Bloods, Nikita, and Supernatural.

ABC
8pm – Shark Tank: (rerun) 1.0 in the demo with 4.05 million.
9pm – Primetime: (season debut) 1.3 in the demo with 3.92 million.
10pm – 20/20: 1.3 in the demo with 4.44 million.

CBS
8pm – Undercover Boss: (rerun) 1.0 in the demo with 4.20 million.
9pm – Hawaii Five-0: (rerun) 0.8 in the demo with 4.63 million.
10pm – Blue Bloods: (rerun) 0.9 in the demo with 6.13 million.

The CW:
8pm – Nikita: (rerun) 0.2 in the demo with 0.94 million.
9pm – Supernatural: (rerun) 0.3 in the demo with 0.90 million.

FOX
8pm – Bones: (rerun) 0.7 in the demo with 2.43 million.
9pm – The Following: (rerun) 0.6 in the demo with 2.07 million.

NBC
8pm – Dateline: 1.4 in the demo with 6.41 million.
10pm – Rock Center with Brian Williams: 1.2 in the demo with 5.28 million.

These are the fast affiliate ratings. The “demo” refers to the viewers in the 18-49 demographic. The percentages represent the change since the previous original episode. (Percentages aren’t given for reruns or specials.) “Million” refers to the total number of viewers.

To see past ratings for a particular show, click the show’s link. The show pages are updated with the daily final ratings when they become available. Those pages include percentage changes in both the demo and total viewership, in addition to season averages to date.

Here are the show season averages, grouped by network: ABC | CBS | CW | FOX | NBC

What were you watching last night? Original episodes, reruns, or something even better?