For the worldâ€™s largest pharmaceutical companies, China is an increasingly critical, yet risky bet.

This map shows each country's gini coefficient, which measures economic inequality. The red countries are the most unequal under the metric, and the green countries are the closest to nationwide economic equality.

Watch the growth of U. income inequality with this animated map (Gini coefficient GIF)

This article introduces the Gini coefficient as a numerical measure of income inequality.