Nearly one third of people killed by US police since 2015 were running away, driving off or attempting to flee when the officer fatally shot or used lethal force against them, data reveals. In the past seven years, police in America have killed more than 2,500 people who were fleeing, and those numbers have slightly increased in recent years, amounting to an average of roughly one killing a day of someone running or trying to escape, according to Mapping Police Violence, a research group that tracks lethal force cases. In many cases, the encounters started as traffic stops, or there were no allegations of violence or serious crimes prompting police contact. Some people were shot in the back while running and others were passengers in fleeing cars. Despite a decades-long push to hold officers accountable for killing civilians, prosecution remains exceedingly rare, the data shows. Of the 2,500 people killed while fleeing since 2015, only 50 or 2% have resulted in criminal charges. The majority of those charges were either dismissed or resulted in acquittals. Only nine officers were convicted, representing 0.35% of cases. The data, advocates and experts say, highlights how the US legal system allows officers to kill with impunity and how reform efforts have not addressed fundamental flaws in police departments. US police kill more people in days than many countries do in years, with roughly 1,100 fatalities a year since 2013. The numbers haven't changed since the start of the Black Lives Matter movement.