Markets have calmed down to the extent that it's actually been 448 days since the last time that the S&P 500 has fallen by 3% or more in a single day. At today's level on the Dow that would be a 400 point decline. For comparison, since 2008 we had grown accustomed to getting a decline that large once every 32 days on average.
Looking at S&P history since 1957, the current 448 day streak is better than average, but not quite at the best levels that the index has ever seen. Over that period, a 3%+ daily decline happens about once every 217 days. However there are several long periods without them. There was no such decline for 11 years between 1962-1973. Even recently there wasn't a 3% decline for nearly 1500 days between 2003-2007. That streak was broken on February 27, 2007.