After Keith Olbermann left MSNBC and was replaced by "Lawrence O’Donnell’s The Last Word," the network’s ratings are down about 10% from the same time a year earlier, reports the Hollywood Reporter.

O’Donnell’s ratings are down 22% from Olbermann’s ratings in the fourth quarter of 2010, the story adds, with both ratings declines noted in the 25-to-54 year old demographic, which is the age group sought by news programs, the story says.

It adds that part of the decline can be blamed on Olbermann’s younger viewers leaving his 8 p.m. time slot after his departure from MSNBC.