According to the Happy Planet Index, an annual survey conducted by the New Economics Foundation, Costa Rica ranks as the happiest country on Earth (“Take a Trip to the Happiest Country on Earth,” Forbes, October 1, 2012). The index takes into account a number of factors including the quality of life and life expectancy, but most important the index values the sustainability of the environment, which it argues “establishes an undeniable link between happiness and the environment or nature.” The World Bank estimates that Costa Rica’s GDP per capita in 2012 was approximately $8,800, about one-fifth that of the United States. Explain why GDP per capita does not always correlate well with a country’s standard of living.