between 1985 and 2015, the S&P 500 stock index budged less than 3 percent from its starting point on 7,663 out of 7,817 days; in other words, for fully 98 percent of the time, the market is remarkably stable.[15] Because the distribution of price changes in these widely traded markets approaches normal, speculators concentrate on harvesting profits from the modest fluctuations that occur on most days.[16]
