American Football Statistics part 2

In the last post, I went through an interesting (for me anyway) observation from a book on the proportion of wins for American football teams. I only gave a chart for the example of the Buffalo Bills team.

Well, I've now put the data together for the rest of the teams and placed it on my site. You can now look at the stats for the rest of the teams:

Or at least those teams that have data from 1960 to 2014. I still find it hard to find much periodicity in quite a few of the teams. And some teams have some quite lengthy periods of high win percentages (San Francisco 49ers):

It's only to be expected that there would be some exceptions. What I should do if I wanted to 'prove' it one way or the other is to calculate the periodicity for each team and then see what correlation we get. Next time maybe.

Data courtesy of www.pro-football-reference.com
Charts courtesy of D3 (www.d3js.org)