In a 2010 Princeton study, Daniel Kahneman and Angus Deaton found that, on average, annual income beyond $75,000 doesn't have a major impact on a person's happiness. The Huffington Post put this map together, looking at the "plateau salary" by each state. The map measures the point at which additional annual income no longer has a major impact on happiness. Wisconsin sits at $74,100, just below the national average.

Image: The Huffington Post