Or at least European. The happiness U-curve. And the happiness EU-curve.
>> The difference in happiness of men between men of my [American] generation, born in the 1960s, and my father's generation, born in the 1920s, is the same as the effect of a tenfold difference in income. In other words, if my father had little money compared to his contemporaries and I have lots of money compared to mine, I can still expect to be less happy. Here, curiously, the European pattern diverges. Happiness falls for the birth years from 1900 to about 1950, and generations born on the continent since World War II have gotten successively happier.