The Gini coefficient measures the inequality among values of a
The Gini coefficient was proposed by Gini as a measure of
There are some issues in interpreting a Gini coefficient. The same value may result from many different distribution curves. The demographic structure should be taken into account. Countries with an aging population, or with a baby boom, experience an increasing pre-tax Gini coefficient even if real income distribution for working adults remains constant. Scholars have devised over a dozen variants of the Gini coefficient.   
The Gini coefficient is usually defined
If all people have non-negative income (or wealth, as the case may be), the Gini coefficient can theoretically range from 0 (complete equality) to 1 (complete inequality); it is sometimes expressed as a percentage ranging between 0 and 100. In practice, both extreme values are not quite reached. If negative values are possible (such as the negative wealth of people with debts), then the Gini coefficient could theoretically be more than 1. Normally the mean (or total) is assumed positive, which rules out a Gini coefficient less than zero.
An alternative approach would be to consider the Gini coefficient as half of the
When the income (or wealth) distribution is given as a continuous
where μ is the mean of the distribution and the lower limits of integration may be replaced by zero when all incomes are positive.