People who hadn't drunk from the pump were not getting sick. And he thought about representing that as a kind of a table of statistics of people living in different neighborhoods, people who hadn't, you know, percentages of people who hadn't, but eventually he hit upon the idea that what he needed was something that you could see.
飲んでいない人は発症しないことが分かってきました 色々な地域の 水を飲んでいない人の割合を 表で示そうかと考えましたが 視覚的に把握できるものが必要と 考え至りました