I don't see how you can draw any conclusions from the data you've provided. This ranking [1] of African countries by Human Development Index [2] has Ethiopia and Liberia ranked 36th and 38th respectively out of 50 countries - all countries ranked below these two (39 to 50) were colonized. You state that these two countries "have the lowest" standards of living; I think most people would argue with your use of "lowest" here. South Africa is ranked 9th, behind the likes of Botswana (6th) and Gabon (8th), and Côte d'Ivoire is ranked 34th. So you think a ranking of 34 out of 50 is high but one of 36 (also out of 50) is low? Or does your source vary significantly from [1]?

1.http://en.wikipedia.org/wiki/List_of_African_countries_by_Hu... 2.http://en.wikipedia.org/wiki/Human_Development_Index