Drawing from an array of data from 126 countries, the report is published today to coincide with "Blue Monday", which has been identified as the most miserable day of the year because of factors including weather, time of year and debt levels.
Its most controversial finding contradicts the widely-held belief that above a certain income level, people do not become any happier.
The theory, conceived in 1974 by wellbeing expert Richard Easterlin, claimed that happiness stagnates when income rises beyond a certain level.
And two years ago, a study at Princeton University claimed to have found that wellbeing stopped increasing at £58,700 - with an increase of as much as a third... read more