Watching Mitt Romney and President Obama discuss the economy doesn’t sound like a huge ratings draw, but the New York Times reports that 67.2 million people tuned in at home, making it the most-watched first debate since 1980. ABC won the night among the broadcast networks, drawing 11.2 million viewers, and on cable the ratings for Fox News were nearly as high, with 10.4 million viewers. (CNN and MSNBC lagged behind with 6 million and 4.7 million respectively.) Even more impressive: Rentrak found that the total audience was fairly constant throughout the hour and a half debate, meaning viewers didn’t change the channel even when it became apparent that the evening would be light on zingers. Just imagine how many Americans will tune in to see ratings magnet Joe Biden next week.