Normal in Books

Google has created a "Books Ngram Viewer" which is a program that allows you to find out how many times a word or phrase has been mentioned in over 5 million books, between certain years. Of course, I had to try "Normal Illinois" and, as you can see from the graph, it wasn't mentioned at all in the late 1800s but peaked in frequency of mentions just before 1960. Local historians could probably explain the changes in frequency.