Very interesting to note that the top developed countries (is South Africa considered developed? Iffy in my opinion) on the list would be:
1 - Hong Kong (53.7)
2 - Singapore (47.8)
3 - USA (45.0)
4 - South Korea (41.9)
5 - UK (40.0)
Its a bit sad that these countries (esp #1 & 2) are on the same level as places like Guatemala, Zimbabwe, Madagascar, and China. I'm not exactly a socialist or communist but large distributions of wealth and poverty is never a good thing. Having traveled to many of the countries here, its really appalling to leave the nice snazzy hotel and see tarps/tents on the road median just in front with families huddled together beneath it.
For Hong Kong & Singapore, I suspect the inequality may be worse than listed because the coefficient doesn't take into account several factors like housing costs (its insane to buy a decent home in Singapore & HK without being rich). For the USA, I'm surprised its so high considering there is still a decently sized middle class there (though shrinking every year). Below, I also show historical Gini coefficient, notice how many countries are increasing in income inequality over time.