This data taken from Robert Shiller, so I trust it to be accurate. P/E ratio in January 1920 was 5.98. By Sept 1929 it had expanded to 32. P/E Ratio in January 1980 was 8.85. By January 2000 it had expanded to 42. In June 2009, (operating earnings) P/E was 25.58. (As reported earnings) P/E was 134.
Silly wabbit trix are for kids. And that is about all P/E ratios are worth to the investing publix anymore. We don't know what we are paying for or what it worth. We just buy because some boob-goon on TV says stocks are cheap. But we don't know relative to what? Yes stock cheap compared to Oct 2007. But is that a valid reference point to rely on?