Exactly. As a former CIA OTS officer to the JAG officer: I understand the need to have boundaries for our troops - in general an effective war machine must be self-disciplined - but there is a place for limited and controlled application of hard interrogation (best done outside of the military structure). There is also a time and place for flat out torture although I would never make that legal because it needs to be rare.
According to CIA docs provided to the Senate Intelligence Committee circa 2009, every CIA officer who volunteered and was subjected to the waterboard...when given the chance to capitulate, capitulated within 20 seconds.
They did not release the number of agents who went through it.
But if you assume 2 for every SERE class (FASO West, it's reported other services never allowed the technique) and 5 CIA guys per year, the number of US Citizens who have experienced the waterboard is certainly less then 5000 and probably around 1000.