Here is a list of percentages of the population with the specified psychological disorder (some percentages may not be entirely accurate):
ADD: 3-5% of the population
Asperger's Syndrome: less than 1%
Autism: less than 1%
Bipolar: about 3%
Depression: 7%
Schizophrenia: 1%
Social Anxiety: 7%
Feel free to add to the list (that is all I could think of for now).