Gini coefficient

measure of inequality in income or wealth distribution

The Gini coefficient (also known as the Gini index or Gini ratio) is a measure of differences in income. It was developed by the Italian statistician Corrado Gini in 1912.

The Gini coefficient by countries (1989-2009)

Definition

The Gini coefficient is usually a number between 0 and 1 (or 0 to 100). 0 means a country where the income is equally distributed. On the other hand, 1 means that one person owns everything but the rest owns nothing. In reality, all scores are between 0.25 and 0.6 (between 25 and 60 on the 0 to 100 scale).

Statistics

The table below is about the world Gini coefficient (not by single countries).

Income Gini coefficient
World, 1820-2005
YearWorld Gini index[1][2][3]
18200.43
18500.53
18700.56
19130.61
19290.62
19500.64
19600.64
19800.66
20020.71
20050.68

The table below shows the income Gini coefficient of the United States from 1947 to 2009.

Income Gini coefficient
United States, 1947-2009
Yearpre-tax Gini
19470.413
19670.397
19680.386
19700.394
19800.403
19900.428
20000.462
20050.469
20060.470
20070.463
20080.467
20090.468

References