True or false: in some areas, nearly 90 percent of native americans were killed by diseases introduced by europeans

True...There were an estimated 18 million Native Americans living north of Mexico at the beginning of the European invasion. Prior to the arrival of the Europeans, American Indians were remarkably free of serious diseases. People did not often die from diseases. As the European explorers and colonists began to arrive, this changed and the consequences were disastrous for Native American people. The death tolls from the newly introduced European diseases often reached 80-90 percent. Entire groups of people vanished before the tidal wave of disease. 

I believe this is true... hope it helps