From the definition:
The Gini index, or Gini coefficient, is a measure of the distribution of income across a population. It is often used as a gauge of economic inequality, measuring income distribution or, less commonly, wealth distribution among a population. The coefficient ranges from 0 (or 0%) to 1 (or 100%), with 0 representing perfect equality and 1 representing perfect inequality. Values over 1 are theoretically possible due to negative income or wealth.
I am wondering where I can get the data of the Gini index? And is there any index similar to this index?