The leaders of Japan and African nations stressed the importance of private sector investment in promoting Africa\'s economic growth as they wrapped up a development conference held once every five years. Tokyo promised 3.2 trillion yen ($32 billion) in government and private-sector aid to the region at the outset of the three-day Tokyo International Conference on African Development. \"We hope to further support and continue to expand together with Africa. We hope to develop a win-win situation in our relationship,\" Prime Minister Shinzo Abe said at a closing press conference Monday in Yokohama. Japan\'s conference for Africa has been held every five years since 1993, according to a report of the Associated Press.