"Ethnic Diversity in Houston, Texas: The Evolution of Residential Segregation in the Bayou City, 1990–2000," stated that Hispanics and Latinos had "intermediate levels of segregation" from non-Hispanic whites. In the early 1980s, there were 300,000 native Hispanics, and an estimated 80,000 illegal immigrants from Mexico in Houston. In 1985, Harris County had about 500,000 Hispanics. Eschbach said that, historically, Hispanics resided in specific neighborhoods of Houston, such as Denver Harbor, the Houston Heights, Magnolia Park, and the Northside. Between 1985 and 2005, the county's Hispanic population tripled, with Hispanics making up about 40% of the county's residents. In most communities inside and outside Beltway 8, Hispanics became the predominant ethnic group. Some communities in Greater Houston which do not have Hispanics as the predominant ethnic group include expensive, predominantly non-Hispanic white communities such as Memorial, Uptown, and West University Place; and historically African-American neighborhoods located south and northeast of Downtown Houston. Eschbach said, "But even these core black and white neighborhoods are experiencing Hispanic inroads. Today, Hispanics live everywhere." Asians Houston also has large populations of immigrants from Asia. In addition, the city has the largest Vietnamese American population in Texas and third-largest in the United States as of 2004. According to a 2002 survey of 500 Asian Americans in Harris County overseen by Stephen Klineberg, a professor at Rice University, Asian immigrants have substantially lower household income than Anglo residents and other immigrant groups, while they have higher levels of education. Indicating the community suffers from severe underemployment. Non-Hispanic Blacks African Americans Historically Houston had a significant African-American population, as this area of the state developed cotton plantation agriculture that was dependent on enslaved laborers. Thousands of enslaved African-Americans lived near the city before the Civil War. Many of them worked on sugar and cotton plantations. Slaves held in the city primarily worked in domestic household and artisan jobs. In 1860 forty-nine percent of the city's population was made up of enslaved people of color. In 1860 nearby Fort Bend County had a population with twice as many black slaves as white residents; it was one of six majority-black counties statewide. From the 1870s to the 1890s, black people made up almost 40% of Houston's population. Before being effectively disfranchised by the state legislature imposing payment of a poll tax in 1902, they were politically active and strongly supported Republican Party candidates. After disfranchisement, the state legislature established legal