“The math of stock market returns blows people’s minds. According to

research from J.P. Morgan Asset Management, the median stock in the

Russell 3000 Index underperformed the overall index by almost 100 percentage points from 1980 to 2014. Fully two-thirds of stocks in the index underperformed the market average over this period. The huge majority—effectively all—of overall index returns came from fewer than 7% of index constituents”