Please answer a question about the following article about Detroit:

While Blacks/African-Americans comprised only 13 percent of Michigan's population in 2010, they made up nearly 82 percent of Detroit's population. The next largest population groups were Whites, at 10 percent, and Hispanics, at 6 percent. According to the 2010 Census, segregation in Detroit has decreased in absolute and in relative terms. In the first decade of the 21st century, about two-thirds of the total black population in metropolitan area resided within the city limits of Detroit. The number of integrated neighborhoods has increased from 100 in 2000 to 204 in 2010. The city has also moved down the ranking, from number one most segregated to number four. A 2011 op-ed in The New York Times attributed the decreased segregation rating to the overall exodus from the city, cautioning that these areas may soon become more segregated. This pattern already happened in the 1970s, when apparent integration was actually a precursor to white flight and resegregation. Over a 60-year period, white flight occurred in the city. According to an estimate of the Michigan Metropolitan Information Center, from 2008 to 2009 the percentage of non-Hispanic White residents increased from 8.4% to 13.3%. Some empty nesters and many younger White people moved into the city while many African Americans moved to the suburbs.

What was Detroit ranked as in a 2010 study on segregated cities?
four