Ngozi Okonjo-Iweala

Nigeria, with the oil sector, had the reputation of being corrupt and not managing its own public finances well. So what did we try to do? We introduced a fiscal rule that de-linked our budget from the oil price.

From 1967 to '70, Nigeria fought a war - the Nigeria-Biafra war. And in the middle of that war, I was 14 years old. We spent much of our time with my mother cooking. For the army - my father joined the army as a brigadier - the Biafran army. We were on the Biafran side.

At one point, I didn't get out of bed for, I think, three months, and I went down to the bottom of the hill one day and I had to call somebody to get me to come back up - come pick me up because I couldn't physically walk up the hill.