The economist has an interesting piece on a study of 19,000 adults in 24 different countries by the research company Ipsos measuring "degrees of happiness". It reaches several counter-intuitive conclusions:
Large, fast-growing emerging markets do not share rich industrialized countries’ pessimism. The already large “very happy” cohort rose 16 points in Turkey, ten points in Mexico and five points in India...thus the highest levels of self-reported happiness is not in rich countries, as one would expect, but in poor and middle-income ones, notably Indonesia, India and Mexico. In rich countries, happiness scores range from above-average—28% of Australians and Americans say they are very happy—to far below the mean. The figures for Italy and Spain were 13% and 11% (Greece was not in the sample). Most Europeans are gloomier than the world average. So levels of income are, if anything, inversely related to felicity. Perceived happiness depends on a lot more than material welfare.