Answer: M*A*S*H

To say that Americans loved M*A*S*H, a sitcom medical drama focused on the activities of a mobile army surgical hospital stationed in South Korea during the Korean War, would be an understatement.

Although the series, which aired from 1972 to 1983, got off to a rocky start (the ratings were so poor in the first season it was almost canceled), it climbed into the top ten shows of the year during its second season and stayed in the top twenty shows for the remainder of its eleven-season run. The show was so popular and so firmly enmeshed in American culture that when it came time for the two and a half hour series finale in 1983 (an extended episode five times longer than the regular show), a staggering 125 million tuned in to watch.

Given that there were only 233 million U.S. citizens at the time of the finale, that means 54% of the entire country sat down on February 28, 1983 to watch. When adjusted against the number of television owning households, the numbers are even more impressive: 77% of the US audience tuned in.

Although in February of 2010 Superbowl XLIV passed the M*A*S*H finale in total number of viewers (a record that had stood strong for the intervening 27 years), it didn’t break the record for ratings or viewer-ship share. In light of how diverse media and television production has become since the 1980s, there’s a good chance that the record M*A*S*H set for total share of U.S. viewers will never be broken.