Well, we’re officially into the summer doldrums. Broadcast TV ratings were fairly ho-hum last week. On cable, however, there is something to talk about.

First, let’s start with the networks. Aside from fresh reality shows (‘America’s Got Talent,’ which ranked first and third, and ‘Duets,’ hanging in there at #19) naturally dominated the Top 20, but lots of repeats (‘NCIS,’ ‘The Big Bang Theory’) helped sustain CBS.

Without ‘American Idol’ until January, FOX got a decent showing from ‘So You Think You Can Dance’ on Wednesday. The big story, though, belongs to the History Channel. And it’s not very often that we say that.

The miniseries ‘Hatfields & McCoys,’ featuring Kevin Costner, averaged 13.8 million viewers Monday through Wednesday. That topped all network programs and was cable’s second-best non-sports broadcast of all time, lagging only behind ‘High School Musical.’

Over on HBO, ‘Game of Thrones’ exited its season with a series-high 4.2 million viewers.

Here’s a look at the Top 20:

1. “America’s Got Talent” (Tuesday, 9 p.m.), NBC, 11.51 million.

2. “NCIS,” CBS, 10.25 million.

3. “America’s Got Talent” (Monday), NBC, 9.96 million.

4. “60 Minutes,” CBS, 9.77 million.

5. “The Big Bang Theory,” CBS, 8.79 million.

6. “America’s Got Talent” (Tuesday, 8 p.m.), NBC, 7.428 million.

7. “Person of Interest,” CBS, 7.425 million.

8. “The Mentalist,” CBS, 7.27 million.

9. “So You Think You Can Dance,” Fox, 7.15 million.

10. “CSI: Crime Scene Investigation,” CBS, 7.06 million.

11. “20/20” (Tuesday, 9 p.m.), ABC, 6.92 million.

12. “NCIS: Los Angeles,” CBS, 6.8 million.

13. “Dogs in the City,” CBS, 6.72 million.

14. “Rules of Engagement,” CBS, 6.43 million.

15. “Miss USA 2012,” 6.29 million.

16. “Adele Live in London,” NBC, 6.22 million.

17. “Dateline NBC” (Friday), NBC, 6.06 million.

18. “48 Hours Mystery” (Tuesday), CBS, 5.98 million.

19. “Duets,” ABC, 5.92 million.

20. “Two and a Half Men, CBS, 5.89 million.