Reading a background report on globalization vaguely related to the G8 meeting I was intrigued to learn about the Gini coefficient:

http://en.wikipedia.org/wiki/Gini_coefficient

which puts income inequality into one number, which is 0 if all people have the same income, and 1 if one person has all the income and everybody else has nothing. (Alternatively, it can be expressed as a percentage, ranging up to 100.)

Interesting comparisons can be made from the World map of Gini coefficients:

Gini coefficient, income distribution by country.

< 0.25 0.25–0.29

0.30–0.34 0.35–0.39 0.40–0.44

0.45–0.49 0.50–0.54 0.55–0.59 ≥ 0.60

N/A

as well as from curves following the coefficient over time. Very embarrassingly for the New "Labour" government here in the UK, inequality has actually increased during their 10 years in power ...

There is a sortable list of countries and their coefficients here:

http://en.wikipedia.org/wiki/List_of_countries_by_income_equality

PS: I think more recent data would show Russia in a different colour ...