So says Nielsen according to the Wall Street Journal, here:
An average of 21.9 million viewers tuned into the nine broadcast and cable networks that were broadcasting convention proceedings Wednesday night between 10 p.m. and 11 p.m., according to Nielsen. That was 41% less than the 37.2 million who tuned in the same night four years ago, the research firm said.
Gee, when Romney loses will they blame the conservatives again?