I was reading this article
https://www.scientificamerican.com/article/what-is-narcissism-science-confronts-a-widely-misunderstood-phenomenon/
'Up to 6 percent of the U.S. population, mostly men, is estimated to have had narcissistic personality disorder during some period of their lives.'
And went to look for more on sex differences in narcissism.
This large study, of over 30,000 people, showed narcissism is far more common in males:
https://www.psychiatrist.com/jcp/medical/comorbidity/prevalence-correlates-disability-comorbidity-dsm-iv-narcissistic-personality-disorder-wave-2-nesarc/
'Prevalence of lifetime NPD was 6.2%, with rates greater for men (7.7%) than for women (4.8%).'
There also seem to be differences in the way NPD manifests in men and women:
'NPD was associated with mental disability among men but not women.'
Further reading suggested that 'gender' or sex stereotyping may also affect how narcissistic traits affect people and how accepted they are by others.