One thing to remember....
Correlation doesn't equal causation. Just because our best years in scoring come in the years that we had the highest run ratio, doesn't mean that we scored more because we ran. In fact, it was most likely the opposite. We ran more because we scored more. Most teams, with the lead, will run the ball to milk clock. Most teams that are behind will pass the ball more to attempt to come back. Typically under Ferentz, our best scoring years came in years where we were equally good at running and passing the ball so the defense couldn't key off of one thing. Then, when we got the lead, we would milk the clock with running plays. So normally we will be 50/50 thru 3 quarters in the run/pass ratio and then run the heck out of the ball in the 4th quarter leading to a final ratio of about 60/40.