A confederation of workers formed in 1886 by 25 craft unions. In 1902, the AFL embraced and encouraged the growth of the early teachers unions. It was a driving force in gaining passage of the SMITH-HUGHES ACT in 1917, providing for federal assistance for the establishment of vocational education in public high schools. The act incurred fierce opposition from private industry, which wanted to control all vocational education through company-operated apprenticeship programs that bound future workers to their jobs by teaching only enough skills to work in a particular company plant and nowhere else. In 1955, the AFL merged with the Congress of Industrial Organizations, an industrial union founded in 1935 to expand unionism to noncraft, assemblyline workers in industries such as automobile manufacturing. At the time, the combined membership of the new AFL-CIO was 15 million, but, as American assembly plants moved to lowerwage areas in foreign countries, union enrollment declined to about 13 million, and the percentage of unionized American workers plunged from 35% of the workforce to a mere 12.5% of all workers and only 7.8% of workers in the private sector. The struggle to preserve rapidly declining non-craft, assembly-line jobs in the United States—and the methods of doing so—produced huge rifts in the AFL-CIO leadership, and, by 2006, five former CIO industrial unions had withdrawn from the umbrella AFLCIO coalition, reducing the number of participating AFL-CIO unions to 52. In 2006, however, the AFL-CIO climaxed a concerted effort to rebuild membership when the nation’s largest union, the NATIONAL EDUCATION ASSOCIATION, announced it would allow its 13,200 local chapters to join the AFL-CIO—a decision that promised to increase AFL-CIO membership by at least one million members.