" In the mutual fund industry, for example, the annual rate of portfolio turnover for the average actively managed equity fund runs to almost 100 percent, ranging from a hardly minimal 25 percent for the lowest turnover quintile to an astonishing 230 percent for the highest quintile. (The turnover of all-stock-market index funds is about 7 percent.) "

― John C. Bogle , The Clash of the Cultures: Investment vs. Speculation