At the end of 2010, the New York City Police Department had the most diverse force in its history, with a majority of rank-and-file police officers coming from minority communities, officials said.

Of the 22,199 officers on patrol, nearly 53% were black, Latino or Asian, marking the first time minorities outnumbered whites by any significant measure, according to police department statistics reviewed by The Wall Street Journal. Minorities had been in a dead-heat with white patrol officers since late 2006, and began inching...