 Deficiency up until the 30s. We had major IQ reduction because of lack of iodine in the U.S. food supply, especially in the U.S. Midwest. From the 30s to the early 80s, the government put crappy iodine in the salt by law. And IQs went up 15 points on average. Burnt defects went way down. And then in the early 80s, they took it out again. This is the Deep Earth Crystal Pure, meaning atomic, on the atomic table.