But it contained the great depression which probably will never happen again. Same for 2000-2010 period. It may be cherrypicking but given that bull markets are much longer than bear markets, the median return from 1940-1970 and then from1980 to 2000 and then from 2010 to now gives you a better idea of the returns going forward. The odds are you will be in one of the 8 winning decades instead of the two losing ones. In the absence of bad decades, and given how low interest rates are , how fat and strong corporate profits are, and low inflation is, real returns of 15-25 percent per year going forward would not surprise me.