African Americans made substantial gains in industrial employment, particularly in the steel, automobile, shipbuilding, and meatpacking industries. Between 1910 and 1920, the number of blacks employed in industry nearly doubled from 500,000 to 901,000. After the Great Depression, more advances took place after workers in the steel and meatpacking industries organized into labor unions in the 1930s and 1940s, under the interracial Congress of Industrial Organizations (CIO). The unions ended the segregation of many jobs, and African Americans began to advance into more skilled jobs and supervisory positions previously informally reserved for whites.