That is the finding of a study by researchers at the University of Illinois on mass killings in the U.S. between 2006 and 2016. Mass killings are defined as homicides with four or more victims:
Recent mass killings, such as those in Newtown, Connecticut, and Aurora, Colorado, have brought new attention to mass killings in the United States. This article examines 323 mass killings taking place between January 1, 2006, and October 4, 2016, to assess how they are distributed over time. In particular, we find that they appear to be uniformly distributed over time, which suggests that their rate has remained stable over the past decade.
This is consistent with a more long-term study that was published by the Congressional Research Service 2015, which dealt specifically with mass shootings (again defined as those with for or more victims), which I wrote about here. It, too, found no increase over time. This chart shows what we think of as “mass shootings” in public places, schools and so on:
So don’t let anyone tell you Donald Trump is responsible for recent mass shooting events. Hurricanes and forest fires, sure; but mass murder, no.