Google Ngram Viewer: Profit, Happiness, and Income in 500 years of texts (Google Books)
The image above charts the frequency of mentions that “profit”, “happiness”, and “income” each had within the 15+ million books/texts that the Google Books project has digitally scanned and databased (over 500 billion words!) since 2004. The graph covers from the year 1500 thru 2008.
Check the live graph here to adjust your own terms and see what interesting graphs you discover about human culture. *Remember that the search terms are case sensitive…