Historical S&P PE Ratio vs. Historical Inflation Adjusted S&P 500

This chart might be hard to read but it is very interesting. On the top is the S&P 500 (inflation adjusted) On the bottom is the PE ratio during this time. The green squares are the time period when the PE is under 10 and the red squares are time periods where the PE is above 20. Looking at the past cycles you would expect PE to fall to the 5-10 range