Chart of The Day: "Today's chart illustrates how the recent rise in earnings has impacted the current valuation of the stock market as measured by the price to earnings ratio (PE ratio). Generally speaking, when the PE ratio is high, stocks are considered to be expensive. When the PE ratio is low, stocks are considered to be inexpensive. From 1936 into the early 1990s, the PE ratio tended to peak in the low 20s (red line) and trough somewhere around seven (green line).