As always, correlation is not causation, so it's very possible that the people who tend to be happier also tend to maybe fit into society better and thus get higher paying jobs, not that you necessarily need to make X/year to be happier.
It is still interesting to see how the actual numbers shake out though, especially the section on how the income quintile groups actually scale linearly instead of log linearly with reported happiness.
It is still interesting to see how the actual numbers shake out though, especially the section on how the income quintile groups actually scale linearly instead of log linearly with reported happiness.