Let's take a look at the 2011-12 season (the ninth and final overall) of One Tree Hill on the CW.
Rating the Ratings: Like Smallville from the previous season, One Tree Hill was able to exit with a little ratings dignity in its final season. -12% doesn't look that great, but on the CW, which had one of the worst seasons for a network in recent memory, it actually meant the show gained ground on most of its peers. It ended up as one of the biggest shows on the network in 2011-12, and only one of the network's other six returning shows (The Vampire Diaries, -11%) dropped less in 2011-12. The season's biggest disappointment was the relative lack of interest in the two-hour series finale, which managed just a relatively average 0.8 demo on April 4. Grade: C+.
Here's the now updated War of 18-49 post for One Tree Hill.