5.4: Percentage of American adults with serious mental illness

9 to 17: Percentage of American children between the ages of 9 and 13 with serious emotional disturbances

16: Percentage of state prison inmates with mental illness

7: Percentage of federal prison inmates with mental illness

33: Percentage of homeless people in the United States suffering from mental illness

Source: “Responding to Emotionally Disturbed Persons,” Laurie Cyr-Martel, Lewiston Police Department