@morpheo In the US 98% (Yes, NINETY EIGHT PERCENT) of cases at the federal level are plead out as guilty because of overcharging and systemic pressures.
98% of people in prison at the federal level never got convicted by a jury trial of any kind, let alone their peers.
As for your idea of what a prison is, we have a substantial chunk of the world's prisoners in total--so what a prison is here very much matters for comparison.
98% are potentially innocent and deprived of their freedom.