The Gini coefficient is a measure used in economics to express the level of inequality in a distribution, such as income or wealth distribution within a population. It is a number between 0 and 1, where 0 corresponds to perfect equality (everyone has the same income) and 1 corresponds to perfect inequality (one person has all the income, and everyone else has none). The coefficient is calculated based on the Lorenz curve, which graphs the proportion of the total income of a population that is cumulatively earned by the bottom x% of the population. The Gini coefficient is essentially the ratio of the area that lies between the line of equality and the Lorenz curve over the total area under the line of equality. A higher Gini coefficient means greater inequality. For instance, a Gini coefficient of 0.3 implies a fairly equitable distribution of income, while a coefficient of 0.7 indicates high inequality. When expressed as a percentage, the Gini Coefficient is expressed from 0 - 100, so 0.3 is equivalent to 30% and so forth.
It's important to note that while the Gini coefficient provides insight into income inequality, it does not give reasons for the inequality or information about absolute income or poverty levels. Moreover, differences in data collection methods and the years of data reported can affect the comparability of the Gini coefficient across countries.