Workers in the 1880s began going on strike to gain better . Only about half belonged to unions. There were an average of about 500 strikes a year between 1881 and 1885. In 1886 this increased to over 1400 strikes. On 4 May 1886 in Chicago a peaceful rally was held to support workers striking for an eight-hour day. Someone threw a bomb into the crowd at Haymarket square. At least eight police officers and several civilians were killed. Labor unions were blamed even though the person throwing the bomb was never caught. The press and the American people held labor unions responsible. As one of the largest labor organizations the knights of Labor were blamed more than the other unions. The Haymarket affair caused the decline of the Knights of Labor even though they were not directly involved. By the early 1900s they were all but gone.