Shiller, a Yale Economist does this in his discussion on evaluating risk:
Note: Video was found from Ritholtz' blog site.
http://www.ritholtz.com/blog/2009/08/yale-economist-robert-shiller-on-evaluating-risk/
...The Good ("Better") News
- There were 8.8 months of supply in June - significantly below the all time record of 12.4 months of supply set in January (Source, here)