During the first half of the 20th Century, The Black Belt was the term for the African-American neighborhood from 22nd Street to 31st Street along State Street on Chicago's South Side. South Side local businessmen and the University of Chicago became alarmed at the prospect of poorer blacks moving from the Black Belt due to a combination of racial succession and economic decline. Because 85% of Chicago was covenanted, most black neighborhoods were bounded by covenanted areas. The Washington Park Court Improvement Association changed its focus from neighborhood improvement projects, such as planting shrubs and cleaning streets, to upholding segregationist policies. When necessary, the organization resorted to violence to pursue its segregationist purpose, and between 1917 and 1921, bombs were used to discourage encroachment into majority white neighborhoods. The bombs were used at the residences of African Americans as well as the properties of real estate agents and bankers.