Narcissism has a broader definition than simple vanity. In 2009, a research study discovered that just over 6% of the U.S. population had been clinically diagnosed with Narcissistic Personality Disorder (NPD).
While statistics do not reflect the truth with complete accuracy, they do provide insight. It is believed that there is a much higher percentage of people who have narcissistic traits such as arrogance and dominance. Depending on the person, these traits may vary in severity, which means there may be a number of people who are at least partly narcissistic.