The world's population is predominantly urban and suburban, and there has been significant migration toward cities and urban centres. The urban population jumped from 29% in 1950 to 55.3% in 2018.[5][6] Extrapolating from the United Nations prediction that the world will be 51.3 percent urban by 2010, Dr. Ron Wimberley, Dr. Libby Morris and Dr. Gregory Fulkerson estimated 23 May 2007 would have been the first time the urban population outnumbered the rural population in history.[7] China and India are the most populous countries,[8] as the birth rate has consistently dropped in developed countries and until recently remained high in developing countries. Tokyo is the largest urban conglomeration in the world.[6][9]