I became aware of Google’s Ngram Viewer a few days ago when Reanna read me the essay “Isn’t the word “feminism” itself gender-biased?” The author used this image:

What? You can do that? Yes, you can, apparently. You can search the frequency of words in all of the books Google has digitized

This is really fun, but be aware that you can sink a lot of time into it. Here are a few randomy ngrams I made. Sorry, but you might have to zoom in to see the text. That’s control-plus for PCs and command-plus for Macs.