It was pretty good. This is 3 years old, but pretty sure nothing has changed with over the air broadcasts since ESPN now has the big games. Here are the top viewed games of all time (at least back to 1991):
http://www.cleveland.com/datacentral/ind...tball.html
35.6 million - ABC, BCS title game/Rose Bowl, Rose Bowl, Jan. 4, 2006, Texas vs USC.
30.8 million - ABC, BCS title game, Jan. 7, 2010, Alabama vs. Texas
30.4 million - ABC, Rose Bowl, Jan. 1, 1996, USC vs. Northwestern.
30.1 million - ABC, Sugar Bowl, Jan. 1, 1993, Alabama vs. Miami.
30.0 million - NBC, Orange Bowl, Jan. 1, 1995, Nebraska vs. Miami.
29.6 million - NBC, Orange Bowl, Jan. 1, 1991, Colorado vs. Notre Dame.
29.1 million - ABC, BCS title game/Fiesta Bowl, Jan. 3, 2003, Ohio State vs. Miami.
29.0 million - ABC, Rose Bowl, Jan. 1, 1998, Michigan vs. Washington State.
28.81 million, NBC, Orange Bowl, Jan. 1, 1994, Florida State vs. Nebraska.
28.80 million - FOX, BCS title game, Jan. 8, 2007, Ohio State vs. Florida.
28.4 million, ABC, Rose Bowl, Jan. 2, 1995, Penn State vs. Oregon.
28.3 million - ESPN, national semifinal/Sugar Bowl, Jan. 1, 2015, Ohio State vs. Alabama.
28.1 million - ESPN, national semifinal/Rose Bowl, Jan. 1, 2015, Oregon vs. Florida State.