The phrase "density of people" is correct and can be used in written English.
Example sentence: The density of people in the downtown area was quite high.
I'm looking for density of people.
"New York has a huge density of eaters and a density of people who are doing excellent things.
In the streets of Kiev last Friday, the density of people wearing orange was almost as great as in Lviv.
In Sarawak the density of people in the southwest makes this region the most important in East Malaysia.
Following the disease epidemic, house finch declines were greatest where the density of people feeding birds also fell dramatically.
That concentration of oil pollution, the authors said, reflects the density of people, vehicles and other sources in the corridor from Washington to Boston.
A Z score of 0 is the mean bone density of people of the same age, sex, and genetic background.
Quite aside from the worrying prospect of dying of overwork, there's the sheer density of people, housing and traffic to contend with.
Romanian fire safety regulations concerning the rooms with high density of people, as conference halls, auditoria, theatres, are based on prescriptions.
"What I love about these sorts of events," explains one committed pillow fighter, "is that a critical mass and density of people arrive in one spot joined loosely by an idea.
