The Gini coefficient is a number between 0 and 1 or 100, where 0 represents perfect equality (everyone has the same income), while an index of 1 or 100 implies perfect inequality (one person has all the income and everyone else has no income).
Income ratios include the pre-tax national income share held by top 10% of the population and the ratio of the upper bound value of the ninth decile (i.e. the 10% of people with highest income) to that of the upper bound value of the first decile (the ratio of the average income of the richest 10% to the poorest 10%).
^Gini coefficient, or Gini index, measures the extent to which the distribution of income (or, in some cases, consumption expenditure) among individuals or households within an economy deviates from a perfectly equal distribution. A Lorenz curve plots the cumulative percentages of total income received against the cumulative number of recipients, starting with the poorest individual or household. The Gini index measures the area between the Lorenz curve and a hypothetical line of absolute equality, expressed as a percentage of the maximum area under the line. Thus a Gini index of 0 represents perfect equality, while an index of 100 implies perfect inequality.
List of EU countries by income inequality based on Gini coefficient
List of countries by income inequality based on different income ratios
List of countries by income inequality based on Pre-tax national income share held by top 10% of the population, Income Decile 1 and Interdecile P90/P10
^Pre-tax national income share held by top 10% of the population (WID): Pre-tax national income is the sum of all pre-tax personal income flows accruing to the owners of the production factors, labor and capital, before taking into account the operation of the tax/transfer system, but after taking into account the operation of pension system. The central difference between personal factor income and pre-tax income is the treatment of pensions, which are counted on a contribution basis by factor income and on a distribution basis by pre-tax income. The population is composed of individuals over age 20. The base unit is the tax unit defined by national fiscal administrations to measure personal income taxes.
^Decile 1 group shares of resource (UNU-WIDER, PIP): A decile is a quantitative method of dividing data into 10 equal parts. Income Decile 1 measures the share of income of the top 10% of the population.
^Interdecile P90/P10 (OECD): The P90/P10 ratio is the ratio of the upper bound value of the ninth decile (i.e. the 10% of people with highest income) to that of the upper bound value of the first decile.