A number that ranges from 0 to 1 – to capture the Income inequality for a COUNTRY. By itself, the number means little, but in comparison with other countries, can convey much.
A GINI index of 1 – would be if ONE family had ALL the INCOME in a country. And 0 would be perfect distribution across every citizen of a country.
The U.S., for e.g.. has a GINI index of close to .46 – which has gone UP from the last 40 years. This means, Income Distribution, though always skewed towards the already wealthy, became more skewed in their favor.