A study conducted by Dube in 2013, showed that the passing of the FAWB in 1994 had an insignificant impact on violent crime in Mexico, while the expiration of the FAWB in 2004 combined with political instability was correlated with an increase in gun-related homicides among Mexican municipalities near the border.[34] Also in 2013, Koper reviewed the literature on the ban's effects and concluded that its effects on crimes committed with assault weapons were mixed due to its various loopholes. He also concluded that the ban did not seem to affect gun crime rates, but may have been able to reduce shootings if it had been renewed in 2004.[35]