San Francisco's ethnic minorities tend to be clumped in relatively small areas, with the Negro population being concentrated in three main districts. This concentration of ethnic groups leads, of course, to racial imbalance in the schools, a problem which is most serious in the elementary schools. If one considers the four main groups of the city to be Negro, Oriental (which includes the city's small Japanese and Filipino population as well as the Chinese), Spanish white, and non-Spanish white, in 1964, 36 of the 96 elementary schools contained 90% or more of one group. Of these, nine were Negro, five Oriental, nineteen Spanish white, and three non-Spanish white. In the junior high schools there is less racial imbalance, but still some: in 1964 two schools were 80% and 61% Oriental; two were 86 and 83% Negro; and two were 85 and 72% white.