From the Centers for Disease Control and Prevention. National, state, and urban area vaccination levels among children aged 19-35 months--United States, 2001.
D002675:Child, Preschool; D006801:Humans; D007223:Infant; D011159:Population Surveillance; D014481:United States / Q000453:epidemiology; D014505:Urban Population; D014611:Vaccination / Q000706:statistics & numerical data*