The article lists household income, which makes it just about useless. Household income will be higher if you are married. People who are married are more likel

The article lists household income, which makes it just about useless. Household income will be higher if you are married. People who are married are more likely to chose a more stable job working for a large corporation. Such jobs require languages more like Java, and less like Haskell. Such people might also have less spare time to play around with new languages due to family engagements, or a dozen other differences, all masked by this chart.