The vertical axis of Figure 3 represents self-reported wellbeing. Those interviewed had to say how satisfied they were with their lives on a scale from 0 to 10. Rating yourself at 10 means you consider yourself maximally happy: you think that, realistically, life couldn’t get any better. Rating yourself at 0 means you consider yourself maximally unhappy: you think that, realistically, life couldn’t get any worse. Most people fall in the middle of this range. The horizontal axis represents annual income.
