What's the real link between income and well-being?

very happyfairly happynot too happy
less 10k354421
10k-20k424215
20k-30k43525
30K-40k55414
40k-50k46469
50k-75k55405
75k-100k60364
100k-150k60400
150k-250k70300
250k-500k83170
more 500k10000
% of US population
Sources: wsj.com brookings.edu