cities within the larger metropolis of Detroit. Detroit, therefore, owes a great deal of its growth to the auto industry. The promise of jobs attracted immigrants from Europe, Asia, and the United States to settle in the Motor City. Originally defined by tightly knit ethnic clusters, the neighborhoods soon began to disperse. As Thomas Sugrue states, "Fewer and fewer white neighborhoods were ethnically homogeneous." Although Detroit remains a large urban center today, it has lost much of its diversity to the suburbs. As a result, the remaining citizens of Detroit—primarily blacks—now face social and economic challenges that prevent them from enjoying lives of quality. Local politics Local politics from the 1870 to the 1910s had been influenced by prominent ethnic communities, especially German Americans and Irish Catholics who controlled the Democratic Party. This changed after 1910 as the old-stock Protestant business leaders, especially from the automobile industry, led a Progressive Era crusade for efficiency, and elected their own men to office, typified by James J. Couzens (mayor, 1919–22, US Senator, 1922–36). The critical change took place in 1918 when the voters changed the Common Council from a 42-man body elected on a partisan basis from 21 wards, to a nine-man unit, elected on a non-partisan basis from the city at-large. The ethnics (especially the Germans) and the Democrats lost their political base. After 1930, however, the Democratic party rebuilt its strength, formed an alliance with the United Auto Workers union and restored the leadership of the ethnics, as typified by Frank Murphy (mayor 1930–33, governor 1937-39). Mayors Jerome Cavanagh (1962–70) and Roman Gribbs (1970-74) were the last of the white ethnic mayors, until 2014. The election of Coleman Young (1974–93) as mayor in 1974 brought to power a new generation of black leaders who represented the city's new majority. Women in the 20th century Most young women took jobs before marriage, then quit. Before the growth of high schools after 1900, most women left school after the 8th grade at about age 15. Ciani (2005) shows that type of work they did reflected their ethnicity and marital status. Black mothers were often day labors, usually as domestic servants, because other opportunities were limited. Most mothers receiving pensions were white and sought work only when necessary. Nursing became professionalized in the late 19th century, opening a new middle-class career for talented young women of all social backgrounds. The School of Nursing