Foreign Policy published on 31 August 2018 a commentary titled "Chinese Aid and Investment Are Good for Africa" by Peter Pham, Atlantic Council, Abdoul Salam Bello, World Bank, and Boubacar-Sid Barry, World Bank.
The authors acknowledge that China held an estimated 15 percent of Sub-Saharan Africa's total debt in 2012 and the number is probably higher now, but they conclude the world stands to gain from China's engagement in Africa. They reported that from 2001 through 2011, China committed nearly $75 billion in aid to the continent. Unfortunately, they do not define aid and it is not clear how much of this "commitment" has been obligated. In any event, this number is considerably higher than most others that I have seen.