The return of 2.92% for the 15-day forward interval is 6 times that of the average 15-day return from 1990 to 2013 of 0.48%.
Interestingly the VIX drop to below 15 is well below its historical average of 20 - but a relatively normal level for what's typically considered a non-volatile market. On the other hand, VVIX (the implied volatility of the VIX index) dropped 17% to almost exactly its historical long-term mean of 86. You could say that volatility traders are neutral on risk right now compared to equity (or index) option traders who appear to believe the worst is over.
8 from 8 is pretty compelling