What proportion of the of the population of japanese-americans died in us concentration camps?

Answer 1

Zero. There was no policy or desire to kill the Japanese-Americans. I'm sure there were some deaths due to natural causes, which it could be argued were attributable to camp conditions or to the stress of being uprooted, but it might just as easily be argued that those people would have died anyway if they were still at home. The camps for the Japanese-Americans were nothing like the camps the Japanese ran for prisoners of war or interned civilians who fell into their hands, in which tens of thousands died, and bore no resemblance to the German death camps. Calling them "concentration camps" became fashionable during the Vietnam era, by those with an anti-government bias, because it carries the sinister implication that they operated on the same plan as the German death camps. Nothing could be farther from the truth.