According to The Economist/YouGov poll, apparently 16.56% of the people surveyed believe that at least an innocent has been executed in the last 5 year, and still supports death penalty.
From the same survey, 62% of respondents answered in favor to the question “28. Do you favor the death penalty for serious crimes such as murder and rape?” It is possible that some of the respondents may only favor death penalty who is proven in a infallible criminal justice system. So theoretically they are not favoring the chance of killing innocents. but still… people have to understand that an infallible system is near impossible in reality. Incidentally 76% of these proponents of death penalty think death penalty is not imposed enough. Wow talk about blood thirsty.
People at the Innocence Project, are you reading this?
All of the data can be found here.