Super Bowl ad spend by year (YoY change):
1) 2017 (Fox) — $419M
2) 2018 (NBC) — $408M (↓ 3%)

Estimated cost per 30s spot by year (YoY change):
1) 2010 — $3.0M
2) 2011 — $3.1M (↑ 3%)
3) 2012 — $3.5M (↑ 13%)
4) 2013 — $4.0M (↑ 14%)
5) 2014 — $4.2M (↑ 5%)
6) 2015 — $4.4M (↑ 5%)
7) 2016 — $4.8M (↑ 9%)
8) 2017 — $5.0M (↑ 4%)
9) 2018- $5.2M (↑ 4%)
10) 2019P — $5.1M — $5.3M

Minutes of ads per Super Bowl (# of spots):
1) 2013: 51:40 (102)
2) 2014: 47:15 (96)
3) 2015: 48:05 (82)
4) 2016: 49:30 (83)
5) 2017: 51:30 (97)
6) 2017: 51:30 (97)
7) 2018: 51:20 (86)

Ad spot length during 2018 Super Bowl:
1) 30s: 51%
2) 1m+: 31%
3) 15s: 11%
4) Other: 7%

More #1: Why Super Bowl Ads Have Become a Harder Sell

More #2: SQAD Data Report: Super Bowl Ad Costs Over the Years

More #3: Super Bowl Ad Price Inflation Lags Regular NFL Season