It's a little weird to compare local crime hotspots to a national average. Costa Rica seems to have about twice the murder rate of the U.S., but that's still low. By "low", I mean if the average accurately represents your risk, it wouldn't be worth worrying about day to day.

Safety is highly situational, and it depends a lot on the way crime happens. If it's criminals killing criminals (e.g. gangs), ordinary citizens and visitors might be fine. But if there is a lot of opportunistic crime, a foreigner might be a target.