Ratings for the Ashton Kutcher era of Two and a Half Men continued to erode Monday night, although they remained at the top of CBS's sitcom block between 8 00 p.m. and 10 00 p.m. and they were 8 percent higher than they were a year ago when Charlie Sheen was the star. Monday night's episode averaged a season-low 9.6 rating and a 15 share (13.8 million viewers) and came in second to ABC's Dancing With The Stars , which averaged a 12.5/19 (17.1 million viewers). NBC debuted Rock Center with Brian Williams at 10 00 p.m. -- with Rocky results. It drew just a 3.3/5 (4.1 million viewers) -- tinier ratings than The Playboy Club , the canceled drama that it replaced. All of the broadcast networks faced competition from NFL football on ESPN on cable.