The NFL and the Lombardi Packers won the first two Super Bowls. Then, each conference went on a long streak:

• The AFL/AAFC won 11 of the next 13 Super Bowls (1968-1980): the Jets and Chiefs closed out the AFL with Super Bowl upsets, while the Steelers, Dolphins, and Raiders carried the AFC.

• Then, from 1981 to 1996, the NFC won 15 of the next 16 Super Bowls, with the 49ers and the NFC East teams (well, not all of them) carrying the conference to 13 of those titles.

• The balance shifted then to the AFC, as the conference won 8 of the next 10 Super Bowls (1997 to 2006).  The Patriots won three of those, but perhaps most surprising was that the run ending with 18-0 New England losing as heavy favorite to the Giants.

Since then? The NFC went on a mini-run, winning 6 of 8 Super Bowls from 2007 to 2014.   The AFC has responded by winning the last two Super Bowls, and the conference is again a favorite in Super Bowl LI. Here are the results in graphic form, with NFL/NFC wins in blue, and AFL/AFC wins in red:

Also of note: the Super Bowl lines. In the first 50 Super Bowls, the AFL/AFC was a favorite 23 times, an underdog 26 times, and the line was a push once (Patriots/Seahawks). But the average line was NFL/NFC -2.3. That’s because the average AFC line, when the AFC team was a favorite, was AFC -5.1. When the AFL/AFC was an underdog? The average was line was +8.9! Even removing the four AFCL Super Bowls, and that line drops to +7.9. This year, with the Patriots favored by 3, it continues the trend of low AFC point spreads as the favorite:

As always, please leave your thoughts in the comments.