Psychologists from Purdue University and the University of Virginia analyzed World Gallup Poll data from 1.7 million people in 164 countries, and cross-referenced their earnings and life satisfaction.  The study, published in the journal Nature Human Behavior researches Happiness, Income Satiation, and Turning Points Around the World.  Les Sinclair interviews Andrew Jebb, the lead author of the study and doctoral student at Purdue’s Department of Psychological Sciences.

https://www.researchgate.net/publication/321743107_Happiness_Income_Satiation_and_Turning_Points_Around_the_World

https://www.marketwatch.com/story/this-is-exactly-how-much-money-you-need-to-be-truly-happy-earning-more-wont-help-2018-02-14