Fox News will finish calendar year 2009 with its highest averages in its history for average viewership (P2+, persons age two and over) in both primetime and total day and during the year it took giant bites of cable news market share. It moved from 41% of the primetime audience in 2008 to 47% in 2009, and 31% of the cable news advertiser target adults 25-54 demographic to 39%.
Although it's impossible to say those gains came from CNN with the data we have, CNN certainly lost tremendous market share in primetime during the year, moving from 26% of the average viewership to just 19%, and from 28% of the demo audience to just 19%, finishing behind MSNBC's 20% for the first time ever in that category.
Headline News also gained share in 2009, although at a lesser rate than Fox News, while MSNBC also lost share, although not nearly at the rate of CNN.
Yesterday, I had a post with the absolute numbers of the changes between 2008 and 2009 cable news primetime and total day viewership and adults 25-54 if you want to see the numbers themselves instead of the market share changes.
2008 : 12/31/2007 - 12/28/2008
2009YTD : 12/29/2008 - 12/16/2009