It's also worth noting the offset between the rate of violent crime and the number of actual executions. The peak number of executions was in 1999, eight years after the peak in the crime rate. (This is due in part to the lengthy -- and growing -- time between sentencing and execution.)
Sanders was responding to comments made by Hillary Clinton in the middle of last week, in which she stated that she didn't agree with how the death penalty had been applied, though she supports it as an option. According to Death Penalty Info, more than one-third of those executed since the death penalty was reinstated in the mid-1970s have been black. Blacks make up 13.2 percent of the country's population.
Clinton isn't alone in her attitude. On Sunday, Jeb Bush told "Meet the Press" that he was similarly conflicted. "[W]e should reform it," he told NBC's Chuck Todd -- citing the length of time it takes to resolve death penalty cases.
That doesn't seem to be something that most Republicans will agree on. According to Pew, 77 percent of Republicans support the death penalty -- a figure that's higher than the level of support among Democrats at the peak of the national crime wave.