According to the latest research by economists, when the annual income is below $ 10,000, the happiness of family members will increase significantly with the increase of family income. However, once the annual income reaches more than $ 10,000, even if the economy continues to prosper, the family income continues to increase, but family members' happiness increases slowly. Based on the above points, we can deduce:. ['Families with less than $ 10,000 in annual income may be happier.', 'Studies show that there is no direct relationship between happiness and money.', 'Survey shows that happiness increases with annual household income.', 'Families earning more than $ 10,000 will face a crisis of well-being.']