In 2011, the latest year for which sentencing statistics are available, fewer than half the defendants who had been arrested for illegal possession of a loaded gun in New York City received a state prison sentence, according to an analysis of criminal justice statistics by the mayor’s office.

In the Bronx, as few as 31 percent were imprisoned. In Brooklyn the rate was 41 percent; in Staten Island it was 47 percent; in Manhattan it was 68 percent; and in Queens it was 76 percent.