One thing to consider is that this case (and the 4%) figure refer to those who've been sentenced to death, where the standards for prosecution and sentencing ar

One thing to consider is that this case (and the 4%) figure refer to those who've been sentenced to death, where the standards for prosecution and sentencing are the absolute highest. It would only be natural to suspect that this figure is even greater the less the sentence/crime. Until we carefully scrutinize the incentives facing the judicial system as a whole (and see how unbalanced it is), this is bound to be the norm.