• by Wayne Friedman , January 6, 2010

Going into its ninth season, "American Idol" looks to continue its winning ways, but this will probably be secured with an increasingly older audience.

"Idol," which has been the highest-rated TV show for the past four years, will again compete against a flow of younger viewers moving away from the show. Older viewers make up a larger composition of the hit program's ratings. The ninth season of "Idol" debuts Jan. 12.

For example, season eight witnessed its best viewer group numbers coming from the adult 35-64 demographic, which averaged an 11.3 rating -- some 13.5 million average viewers, according to Brad Adgate, senior vice president and corporate media director at Horizon Media.

This demo group was down 6% from the year before -- one of the groups that was hit the least year-to-year. These numbers have not changed much over the last five seasons, starting in 2005 when it was at an 11.0 rating, then moved to a 12.8 (2006), 12.8 (2007), 12.0 (2008) and an 11.3 (2009).

At the same time, ratings in season eight for teens 12-17 and adults 18-49 were the lowest since season one. Among the key 18-49 viewers, ratings were down 11% to a Nielsen 9.1 live-plus-same-day rating. It had its highest numbers in 2006 with a 12.4 rating average.

Among the younger 18-34 viewer group it was down 12% to a 7.4 live-plus-same-day rating. Teens were at a 6.1 rating, down 13% from the year before. Total viewers averaged 24.9 million, down 7% from the year before.

Last season, the show pushed up its median age once again, reaching a 44.2 from 43.2. This is up 12.3 years from season one, when the median age was 31.9.

Good news for Fox is that the show still demonstrates strength against the biggest of special TV events. For example, Adgate says "Idol" was one of the few shows -- also with ABC's "Grey's Anatomy" -- that generated higher viewers in head-to-head competition opposite the 2006 Winter Olympics in Torino.