A meta-analysis conducted by researchers at Universidad Complutense de Madrid in Spain estimates the "prevalence rate of psychopathy in the general adult population at 4.5%."
The rate is higher in males and lower in females. It found that "psychopathy levels are higher in North American male and female prisoners than in European male and female prisoners."
The paper also listed occupations most likely and least likely to be filled by psychopaths:
In the United Kingdom, the 10 professions with the highest levels of psychopathic traits were company CEOs, lawyers, radio or television characters, salespersons, surgeons, journalists, priests, police officers, chefs, and civil servants. On the other hand, the 10 professions with the lowest levels of psychopathic traits were social-health assistants, nurses, therapists, artisans, stylists, charity workers, teachers, creative artists, physicians, and accountants.