The United Nations Conference on Trade and Development has just published the TDR 2012, on growth and inequality. Not surprisingly the TDR says that "rising inequality is [not] a necessary condition for sound economic growth." The table below shows the regional evolution of inequality since the 1980s.
As the report shows: "Empirical evidence shows that increasing income inequality has been a feature in the world economy since the early 1980s. However, in the 2000s in Latin America and in parts of Africa and South East-Asia income inequality fell in a context of improved external conditions. The evidence suggests that the relationship between growth and inequality is complex and can be altered by proactive economic and social policies."