As Luca Masters points out in the comments below, it has been a pretty good decade for Africa in economic terms. Below is a chart that sketches average GDP per capita growth. This is a lazy graph created with Wolfram alpha. Much cooler animations could be created with the incomparable gapminder that would show how unusual this uptick in African GDP really is (although I must admit that I find their bubble animations not always so useful for interpreting trends).
ps. Note also that this is the average (mean) not the median GDP per capita in Africa and that I am a little unsure about the precise sources (the graph looks a little too good to be true). There is no doubt about the message of a positive trend, though.