...Juries that impose death are a political mix and those like me who cannot impose it are excluded in jury selections which is kinda why so many people are on death row. The system is rigged to kill people.
Since 1976, 1414 (about 35/yr) have been executed but I doubt that the existence of the penalty stops any crimes. I'll stipulate to the possibility that some executions were unjustified if you will admit that most - and many who weren't executed - more than deserved it.