i wrote an entire book about that called predicting the markets of to morrow by looking at the real 20 year rate of return, so real means te play shond adjust it. And what i found, and you probably see this coming, was when we had come off a fantastic 20 year period with digit returns the next 20 years were awful. Many of those stocks ended up going bankrupt. So just as soon as you think you've got a lookback problem addressed, along comes somebody who does his research like mc quary and trew up k back to the drawing board. I still find it, like you, very interesting and instructive.