Google trends still lists Nigeria as having the worldwide highest interest in bitcoin, but that is fading. Here is the Nigerian interest level in bitcoin over the last year.
that doesn't prove anything. there has been a lot of talk around that time about bitcoin in Africa and obviously could have sparked some interest over there.
also it is the same time as the price rises of end of 2016 and reaching the ATH and again obviously the price rise always brings more people and attention to bitcoin.