As "Big Brother" heads toward the conclusion of its 12th season on Sept. 15, the program is having a strong summer in the ratings.

Nielsen said the CBS reality show is averaging 7.6 million viewers for its three weekly episodes, a 6 percent increase from last summer's 7.2 million average. Among viewers 18 to 34, ratings are up 10 percent.

"We've been thrilled with the ratings this summer," said Allison Grodner, executive producer. She's been with the show since its second season, when "Big Brother" started to emphasize game-playing over the simple voyeuristic experience of watching strangers live together.

Last week all three of its episodes finished among Nielsen's top 12 most-watched shows. For comparison, the only thing on Fox to reach that many viewers was an exhibition football game, and the only thing on ABC was Tuesday's edition of "Wipeout."

For the week, CBS topped the prime-time ratings with an average of 6.6 million viewers. NBC, buoyed by a strong showing by the Emmy Awards, was a close second with a 6.4 million average. NBC tied with Fox, which averaged 5.1 million viewers overall, for the lead among the demographically desired group of viewers 18 to 49. ABC averaged 4.3 million viewers.

ASSOCIATED PRESS

1 Emmy Awards (NBC)

2 America's Got Talent, Tue. (NBC)

3 America's Got Talent, Wed. (NBC)

4 NFL Preseason: Steelers vs. Broncos (Fox)

5 NCIS (CBS)

6 60 Minutes (CBS)

7 Two and a Half Men (CBS)

8 The Big Bang Theory (CBS)

9 Big Brother, Wed. (CBS)

10 Wipeout, Tue. (ABC)

11 Big Brother, Thu. (CBS)

12 Big Brother, Sun. (CBS)

13 NCIS: Los Angeles (CBS)

14 The Mentalist (CBS)

15 Criminal Minds (CBS)

16 NFL Preseason: Cowboys vs. Texans (CBS)

16 Minute to Win It, Wed. (NBC)

18 CSI: Miami

19 Minute to Win It, Tue. (NBC)

20 NFL Pregame Show (Fox)