One year after the Dallas Cowboys embarrassed the Buffalo Bills, 52-17, in Super Bowl XXVII, the Cowboys were a 10.5-point favorite over the Bills in Super Bowl XXVIII, the first (and only) rematch in consecutive years in Super Bowl history. It was the first double-digit Super Bowl spread in five years and just the fourth since the first four Super Bowls featured spreads of at least 12 points.
The Cowboys covered in Super Bowl XXVIII, scoring 17 unanswered points to win 30-17 after falling behind 13-6 in the first half. It was the first of five straight Super Bowls with a spread of at least 10 points:
XXVIII: DAL -10.5 (vs. BUF)
XXIX: SF -18.5 (vs. SD)
XXX: DAL -13.5 (vs. PIT)
XXXI: GB -14 (vs. NE)
XXXII: GB -11 (vs. DEN)
A year after the Cowboys covered 10.5 points vs. the Bills, the San Francisco 49ers covered the biggest spread in Super Bowl history in smashing the San Diego Chargers. The Cowboys didn’t cover in 1996, the Packers pushed in 1997, and the Packers didn’t cover in 1998. Since the Denver Broncos disposed of an 11-point line in January 1997, with few exceptions, Super Bowl lines have plummeted.
Even with low numbers throughout most of the 1970s and 1980s, the average Super Bowl spread from 1967 (Super Bowl I) through 1997 (XXXII) was 7.8 points. Average line since 1998 (including the Super Bowl LV): 5.1 points. Of the eight games with a spread of 2 points or fewer, five have come in the last 10 years, including the third-ever 1-point line, the Seattle Seahawks over the New England Patriots six years ago.
The line hasn’t exceeded 4.5 points since the Indianapolis Colts were 5-point favorites over the New Orleans Saints in Super Bowl XLIV in 2010. The average over those 10 years–2.95 points–is the lowest ever over any 10-year period.
While we saw a dramatic increase in spreads 25 years ago when Super Bowl XX (10 points) ended a 15-year run with an average of 4.2 points, that occurred long before online sports betting exploded in popularity and has kept spreads within one score.