由布鲁金斯学会的非洲增长倡议课题组和联合国大学世界发展经济研究所联合进行的新研究可能拥有解答这个问题的钥匙。
New research by the Brookings Institution’s Africa Growth Initiative and the United Nations University World Institute for Development Economics Research (UNU-WIDER) might hold the key to answering that question.