The life of Ngozi Okonjo-Iweala is full of very high figures, even for an economist. As president of Gavi, the Vaccination Alliance, she has led the annual immunization of millions of children. When she was CEO of the World Bank, she oversaw operations worth $ 81 billion. In his time at the head of Nigerian finances, he took on a debt of 30,000 million dollars from the most populous country in Africa. And he has 1.5 million followers on Twitter.