on Efficiency, Depression, Happiness, and Beer

The Google Ngram viewer charts the incidence of terms in 5.2 million books dating back centuries. It's a pretty amazing tool.Choosing the words 'efficiency' and 'depression' I graphed their usage over the last 500 years. I found a close correlation between the terms, with both beginning to rise around 1750 and sharply peaking around 1925. As a control variable I also included 'weather', which showed little correlation to either efficiency or depression. Something to think about as we continue to make ourselves faster, better, and stronger![youtube=http://www.youtube.com/watch?v=gAjR4_CbPpQ]****EDIT****To avoid being too much of a downer on a Friday, I want to also include my findings on the relationship between happiness and beer. If this doesn't demonstrate true progress, I don't know what will - we've almost reached equilibrium!I don't expect to break any ground with these findings, I just wanted to share what is a very fun set of data to play around with. For more nuanced and careful analysis, see the book 'Uncharted - Big Data as a Lens on Human Culture' by Aiden and Michel.