One group that has seen a decline in living standards is the Black population of Seattle.
http://blogs.seattletimes.com/fyi-gu...ds-get-poorer/
Should be noted though that Seattle has seen an influx of East African immigrants, and now about 30% of Seattle's Black population is foreign born, and East Africans have very low average incomes. African Americans have been leaving the city in significant numbers, like in San Francisco. Yet this immigrant influx has kept the city at about 8% Black, had it not occurred the city would probably only be around 5-6% Black.