This is from the Hack It Out podcast. It is very good and discusses timely topics and some have stats from Lou Stagner. The website can be found here.
The episode for Aug 7th discusses the average number of fairways hit when a 10 Index (HDCP) plays really well vs when they play really poorly. There are no "official" fairways on Par 3 holes, so almost all courses have 14 fairways for they have two Par 3's on each Nine.
The answers are for 10 Index...
Play Really Well - 7.1 fairways
Play Really Poor - 6.3 fairways
That is less than 1 fairway difference between really good and really bad rounds. The difference comes from what happens on those missed fairways - i.e. penalty shots (water, out of bounds, etc.) and recovery shots (under trees, really thick rough, etc). It is so important to keep the ball out of trouble!