ST. PETERSBURG, Fla. (AP) The stand your ground self-defense law had been in effect in Florida for more than six years when it became part of the national vocabulary with the death of Trayvon Martin in 2012. When the 17-year-old was fatally shot, Florida was still one of the few states with the law that removes the duty to retreat before using deadly force in the face of danger.

Now, upward of 30 states have some form of the law and recent research indicates they are associated with more deaths as many as 700 additional firearm killings each year, according to a study published this week in the journal JAMA Network Open .

The study found that stand your ground laws in those states could be associated with a national increase of up to 11% in homicide rates per month between 1999 and 2017. The largest increases, between 16% and 33%, were in Southern states including Alabama, Florida, Georgia and Louisiana, the study found.

These findings suggest that adoption of (stand your ground) laws across the U.S. was associated with increases in violent deaths, deaths that could potentially have been avoided, the studys authors concluded.

Advocates for the laws, especially the National Rifle Association, have argued they act as a crime deterrent by ensuring a person can protect themselves and others against a would-be assailant.

Florida was first in the nation in 2005 to adopt such a law. It was in force when Martin was fatally shot by self-appointed neighborhood watchman George Zimmerman on Feb. 26, 2012. Martin was Black; Zimmerman had a white father and Hispanic mother.