In 2014, the Denver Broncos ranked 4th in Adjusted Net Yards per Attempt; in case you forgot, Peyton Manning‘s “struggles” last year were really confined to the back end of the season. This year, the Broncos rank 31st in ANY/A, as Manning has been terrible and Brock Osweiler has been far below average. The Broncos ANY/A has dropped from 7.67 to 4.90, a decline of 2.77 ANY/A.

But that’s not even the biggest decline of 2015. Last year, the Dallas Cowboys ranked 2nd in ANY/A at 7.96; this year, without Tony Romo, the team is dead last at 4.76, for a decline of 3.20 ANY/A. Here is the full list of how passing offenses have improved/declined from 2014, which also shows why Carson Palmer is a pretty good choice for MVP:

Drastic swings in ANY/A more common long ago, when teams threw fewer passes (leading to unsustainable high/low ANY/A averages driven by small sample sizes) and interceptions (which cause large swings in ANY/A) were also a bit more varied. The 1932 Cardinals had a respectable 3.9 AY/A average ^[1]For seasons prior to 1969, we have to use AY/A, not ANY/A, due to the lack of sack data available. which was the product of 2 TDs, 4 INTs, and a 5.0 Y/A average on 126 passes. In 1933, on 139 passes, the Cardinals averaged 3.4 Y/A with 3 TDs and … thirty interceptions, which caused the team’s AY/A average to plummet by 9.77 to -5.90. No other team in history is even within 3.5 AY/A of that sort of decline.

If we limit our sample to just the post-merger era, the Cowboys decline would rank as the 4th worst ever. The table below shows the biggest declines in ANY/A, year over year, from 1970 to 2014. It also lists the quarterback with the most pass attempts in both seasons:

In 1973, Bob Lee led a solid Falcons passing attack that averaged 4.82 ANY/A, good enough for 10th best in the 26-team NFL. In 1974, Lee, Pat Sullivan, and Kim McQuiklen were disasters, throwing four touchdowns against 31 interceptions, producing an ANY/A of -0.02.

In 2009, Brett Favre had one of the best seasons of his career; in what may have foreshadowed what has happened to Manning, he then had arguably the worst season of his career at age 41. A similar story involves Bart Starr, who fell off dramatically from his age 35 season in 1969 to his age 36 season in 1970.

At this page, the 2015 Cowboys will occupy the next spot on the list. It’s been that kind of year for Dallas. The Cowboys rank 1st in interception rate and yet in the bottom three in both touchdown rate and yards per completion; that sort of high-risk, low-reward passing attack is tough to pull off.