Non-Hispanic whites, African-Americans, and Asians are defined as those respondents who checked only a single "race" on the Census questionnaire. The fact that more and more people have felt it appropriate to check two or more "races" on this form surely has at least some effect on decade-to-decade population comparisons. For example, some of apparent population declines of people associated with a single "race" might be exaggerated.
The heavy solid black line in these maps indicates the Chicago city limits. The thin dark grey lines are census tract boundaries. All 2010 statistics have been recompiled to fit 2000 tract boundaries, generally by assigning 2010 data to the 2000 tracts in which 2010 tract centerpoints fell. This should present no great problem where tract boundaries were unchanged or where tracts were split, conditions that apply to ca. 98% of the census tracts in the Chicago area. In cases where more complicated tract boundary changes occurred, it is likely that the maps err in small ways. The location of dots within tracts is random.