According to current epidemiological estimates, at least one in five
people has a diagnosable mental disorder during the course of a year
(i.e., 1-year prevalence).

1 in 5 is 20%

In the early 1950s, the rates of mental illness estimated by
epidemiologists were far higher than those of today. One study, for
example, found 81.5 percent of the population of Manhattan, New York,
to have had signs and symptoms of mental distress (Srole, 1962).

Also,

[url=http://www.surgeongeneral.gov/library/mentalhealth/chapter2/sec2_1.html]The...

According to current epidemiological estimates, at least one in five
people has a diagnosable mental disorder during the course of a year
(i.e., 1-year prevalence).

1 in 5 is 20%

In the early 1950s, the rates of mental illness estimated by
epidemiologists were far higher than those of today. One study, for
example, found 81.5 percent of the population of Manhattan, New York,
to have had signs and symptoms of mental distress (Srole, 1962).

Also,

The current prevalence estimate is that about 20 percent of the U.S.
population are affected by mental disorders during a given year. This
estimate comes from two epidemiologic surveys: the Epidemiologic
Catchment Area (ECA) study of the early 1980s and the National
Comorbidity Survey (NCS) of the early 1990s. Those surveys defined
mental illness according to the prevailing editions of the Diagnostic and Statistical Manual of Mental Disorders
(i.e., DSM-III and DSM-IIIR). The surveys estimate that during a 1-year
period, 22 to 23 percent of the U.S. adult population—or 44 million
people—have diagnosable mental disorders, according to reliable,
established criteria.

It seems war service or military service does not lead to more prevalence of mental problems. But that doesn't stop 'sicko' from continuing to have such a low opinion of the intellect of those who buy what he is selling.