This is a list of countries or dependencies by income inequality metrics, including Gini coefficients. The Gini coefficient is a number between 0 and 1, where 0 corresponds with perfect equality (where everyone has the same income) and 1 corresponds with perfect inequality (where one person has all the income—and everyone else has zero income). Income distribution can vary greatly from wealth distribution in a country (see List of countries by distribution of wealth). Income from black market economic activity is not included and is the subject of current economic research.