Pretty interesting stuff from Mile High Report. Check it out-

So one thing that is often talked about by fans across the NFL is trends, becoming a more pass happy league, a QB driven league, weakening of the running game. Well I have always heard of these trends, and seen basic data proving or disproving them, but I wanted to take a deeper look myself at what's trending across the NFL.

So with this goal in mind, I set out to look at offensive, defensive and special teams, and how they've changed as time has passed. Now I was planning on doing this in one post, but there was so much to write, I decided to break it down into separate posts reviewing offensive trends, passing and rushing, and defensive trends, and a final post with special teams with a conclusion piece which will give a brief summery of all that I found. So there will be a total of four articles.

So with that in mind, today we will be looking at the NFL passing game and how it has changed over the years in a number of areas, that will hopefully give us a better idea of what direction the NFL is headed in. I realize this is pretty table and data heavy, so I wish any and all who enter good luck, God speed, and hopefully we'll see you at the end.

Preview and Methods: So I set out to look at the modern NFL and how it has changed. To do this, I looked at the NFL's full history as well as considered when new offenses became popular and when rule changes came into play, and I decided on 1978, which was the beginning of a number of major rule changes in the NFL, as well the starting point for many great quarterbacks, and this is also the time many refer to as the beginning of the age of the quarterback. So with that in mind, I looked at every year from 1978 to 2010. A few key years to note would be 1982, which was shortened to nine games. In 1995 the NFL went from 28 teams to 30 teams by adding the Carolina Panthers and the Jacksonville Jaguars. In 1999 the Cleveland Browns returned, and in 2002 the Houston Texans joined the league, leaving us at our current 32 teams.



http://www.milehighreport.com/2011/6/20/2230763/some-clarification-is-in-order-the-passing-game-nfl-trends