There have been 355 mass-shootings so far this year.
This statistic has been widely quoted, but it is a bit misleading. If you count every guy who shot at more than one person while robbing a liquor store a "mass-shooting", then yes, you will have stats like that. The truth is that we have had something like 74 true spree-shooting in the past 21 years. I might be mildly off, but I know I am correct or fairly close. Don't mix up all of the dopes robbing a convenience store with the loons who go into a movie theater and shoot people with the pure intent to kill.
Also, gun ownership has gone up more than 50% in the past 20 years and gun violence has actually dropped by about the same amount. It is just the big, flashy, spree-killings that are happening more often in recent years/month that make people nervous.