A recent analysis of U.S. gun deaths has found that a majority of mass shootings were related to domestic or family violence.

The analysis, performed by Michael Bloomberg's gun violence prevention group, Everytown for Gun Safety, looked at mass shootings that took place between January 2009 and July 2014. In that span of five and a half years, the group identified 110 mass shootings, which were defined as shootings in which at least four people were murdered with a firearm. Of those shootings, at least 57 percent were related to domestic or family violence.

Kim Gandy, president of the National Network to End Domestic Violence, said the report serves as sobering evidence for the need to improve gun laws.

"It’s clear that many of these murders were committed by people already barred from gun ownership by federal law -- but that law is full of loopholes, like background checks not being required for private sales, like Craigslist or at gun shows," she said. "It’s shocking that the gun lobby has succeeded in blocking such common-sense solutions, and that there aren’t more members of Congress standing up on the issue."

Research has shown that women in abusive relationships are eight times more likely to be killed if their abuser has access to a gun.

Under federal law, individuals who have been convicted of a misdemeanor domestic violence offense or who are subject to a permanent domestic violence restraining order can’t legally buy or possess firearms. But many guns are purchased without a background check, making thorough enforcement of current laws all but impossible.

In addition, federal gun prohibitions only apply to situations where the perpetrator is married to the victim, or cohabited with or has a child with him. Dating partners and convicted stalkers are not included, and those loopholes allow many domestic abusers to dodge the background check system.

According to the Everytown analysis, in one-quarter of the mass shootings in which the perpetrator killed a former or current partner, the perpetrator would not have been barred from owning a firearm.

It's worth noting that mass shootings make up a tiny share of U.S. gun homicides. In 2012, less than 1 percent of gun homicide victims were killed in mass shootings, according to FBI data.