Measures of income inequality are based on data on people's household disposable income (see "Definition and measurement" in GE1 for more detail). The main indicator of income distribution used is the Gini coefficient. Values of the Gini coefficient
range between 0 in the case of "perfect equality" (each person gets the same income) and 1 in the case of "perfect inequality" (all income goes to the share of the population with the highest income). Life expectancy data is discussed in "Definition
and measurement" of indicator HE1.