Measuring the Popularity of Sports

What's the best way to measure a sport's popularity? Let's start with average viewers on national broadcasts.

If you were looking at that chart, would you say there are 3, 4 or 5 major sports? To me it looks like there's 1 major sport.

Here's an interesting chart of peak events, by sports:

(I even went back to the 2017 list to see a MLS peak, but soccer peak that year was a US-Mexico qualifier.)

The bottom line is that football dominates everything. NBA is ahead of MLB. College football and basketball are still doing well. And NHL and MLS are really in the same tier as NASCAR and golf and the rest. 

Sources:

https://www.sportsmediawatch.com/2018/04/nhl-viewership-nbc-nbcsn-regular-season/
https://finance.yahoo.com/news/u-sport-had-highest-viewership-141700953.html