A major decline in manufacturing in northern cities, with a shift of jobs to suburbs, the South, and overseas, has led to increases in the numbers of residents of all races in suburbs, and shifts in population from the North and Great Plains to the southwest, the Pacific Northwest, and the South. Left behind in many northeastern and midwestern inner cities have been the poorest Black people and other minorities. According to Jonathan Kozol, in the early 21st century, US schools have become as segregated as they were in the late 1960s.