New York City is on track to have fewer than 500 homicides this year, by far the lowest number in a 12-month period since reliable Police Department statistics became available in 1963.
But within the city’s official crime statistics is a figure that may be even more striking: so far, with roughly half the killings analyzed, only 35 were found to be committed by strangers, a microscopic statistic in a city of more than 8.2 million.
If that trend holds up, fewer than 100 homicide victims in New York City this year will have been strangers to their assailants. The vast majority died in disputes with friends or acquaintances, with rival drug gang members or — to a far lesser degree — with romantic partners, spouses, parents and others.
The low number of killings by strangers belies the common imagery that New Yorkers are vulnerable to arbitrary attacks on the streets, or die in robberies that turn fatal.
In the eyes of some criminologists, the police will be hard pressed to drive the killing rate much lower, since most killings occur now within the four walls of an apartment or the confines of close relationships.
“What are you going to do, send cops to every house?” said Peter K. Manning, the Brooks professor of criminal justice at Northeastern University in Boston.
“We know that historically, homicide is the least suppressible crime by police action,” he added. “It is, generally speaking, a private crime, resulting from people who know one another and have relationships that end up in death struggles at home or in semipublic places.”
Police officials did not dispute the validity of that assessment.
The homicide figure continues a remarkable slide since 1990, when New York recorded its greatest number of killings in a single year, 2,245, and when untold scores of the victims were killed in violence between strangers.
Homicides began falling in the early 1990s, when Raymond W. Kelly first served as police commissioner, and plummeted further under subsequent commissioners. Mr. Kelly returned to serve under Mayor Michael R. Bloomberg in 2002, the first year there were fewer than 600 homicides. There were 587 that year, down from 649 in the previous year.
Nearly two decades ago, the city’s crack-cocaine epidemic led to headlines about gang wars, semiautomatic gunfire in schoolyards and a police blotter that showed more than six homicides a day, on average.
This year, with 428 killings logged through Sunday — 412 actual killings plus 16 crime victims who have died this year from injuries sustained long ago — the average number of killings is a bit more than one a day.
The numbers on file from before 1963 are not considered reliable for comparison because until then, many homicides were not recorded until an arrest was made and the case was closed, but ever since, they have been recorded as they occurred. There were 390 homicides recorded in 1960, fewer than this year, but any comparison would be faulty.
The killings that have seized the headlines this year appear to have personal motives at their core: An assistant has been charged with killing her boss, Linda Stein, inside Ms. Stein’s Fifth Avenue penthouse after a vicious argument; a Queens orthodontist, Daniel Malakov, was gunned down, and a relative of his estranged wife, whom he was fighting in divorce and child custody proceedings, has been charged.
In contrast to the 35 cases this year in which officials have found that victim and assailant were strangers, there were 121 in the whole of last year, officials said. The motives in the remainder of the killings this year are still being analyzed.
The dropping homicide rate raises a question of whether other types of crime are on the rise. But police statistics, which are subject to an internal auditing system in use since the early 1990s, show dips in six of the seven major crime categories, according to the department’s latest reports.
As of Sunday, overall crime was down 6.47 percent, compared to the same period last year. In addition to the homicide rate, the number of rapes, robberies, burglaries, grand larcenies and car thefts are all on the decline.
Felony assaults have increased slightly, to 15,372 from 15,344, a 0.1 percent increase, according to the police statistics. Shootings, which the department has tracked for 14 years, as well as the number wounded in those shootings, are both down.
After years when crime fell across the nation, many cities in the country are now experiencing a surge in homicides, said Thomas A. Reppetto, a police historian who monitors the city crime numbers and helped write “NYPD: A City and Its Police.”
“You would expect New York to follow the national trend, but instead, murders continue to go down considerably,” Mr. Reppetto said.
“Not only has the N.Y.P.D. reduced murder, by nearly 80 percent, but it has changed the pattern of homicides,” he added. “In the early 1990s, many innocent citizens were killed by bullets from battling drug gangs. Today, thanks to the police drive against the gangs, that type of homicide is far less common.”
It is extremely common around the nation to find in killings involving acquaintances that those involved are not family members but criminals or drug gang members, said David M. Kennedy, the director of the Center for Crime Prevention and Control at the John Jay College of Criminal Justice in Manhattan.
In the 412 killings this year, the number of people with previous arrests for narcotics was striking: 196 victims and 149 assailants. And 77 percent of the assailants had a previous arrest history, while 70 percent of the victims did, the statistics showed.
Killers and those killed are overwhelmingly male and most in both categories are between 18 and 40, according to the police analysis. In terms of race and ethnicity, whites make up 7 percent of victims and assailants, while 66 percent of the victims and 61 percent of the assailants are black and 26 percent of the victims and 31 percent of the assailants are Hispanic.
When told about the low homicide numbers, Dr. Manning uttered a single word: “Wow.”
Mr. Kennedy said, “What this shows is that the N.Y.P.D. — and whatever else is going on in New York — has managed to squeeze the problem of active offenders against active offenders down to a remarkably, historically low level.”