The premiere started off with a bang: "The 13th season premiere of "Big Brother" won the evening's top ratings on Thursday and beat out its previous season premiere, according to preliminary viewership figures."
http://www.reuters.com/article/2011/07/08/us-ratings-idUSTRE7645JD20110708"Big Brother" on CBS at 9 p.m. received a 2.7 rating/8 share in the adults 18-to-49 viewer group, an eight percent climb over the season launch last July, and 7.7 million total viewers."