 Washtenaw has the highest proportion of Asian-American residents of any Michigan county.As of the 2000 census of 2000, 17.4% of county residents were of German ancestry; 9.0% cited English, 8.4% Irish, 5.3% Polish and 5.0% American ancestry.According to Census 2000, 87.1% spoke only English at home; 2.7% spoke Spanish and 1.7% Chinese or Mandarin.