Between 1940 and 1960 the total population of U.S. metropolitan
areas increased by forty million persons. Eighty-four per cent of
the Negro increase occurred in the central cities and 80 per cent of
the white increase, in the suburbs. Suburbanization of whites accelerated
between 1950 and 1960; nearly 90 per cent of their metropolitan
increase occurred in the suburbs. An even sharper contrast
appears in the twenty-four metropolitan areas with populations of
over one million in 1960. In the two decades between 1940 and 1960
almost 100 per cent of the increase in their white populations was
absorbed by the suburbs. Between 1950 and 1960 their central
cities lost nearly one and a half million white residents and gained
more than two million Negroes.9 Moreover, these data understate
the differences in the rate of suburbanization of whites and Negroes. .