No one thinks New Orleans teens have suddenly become homebodies.

Yet reported incidents of curfew violations are down a whopping 79 percent in less than five years.

Drunken driving may be on the wane, as national highway fatality figures suggest — but nothing like the 39 percent slide in reported DWI incidents in the Big Easy.

And on down the line: Suspicious persons incidents are down 63 percent; illegal gun incidents, off 30 percent; drug incidents, down 20 percent.

What these crimes have in common is that they tend to come to light when cops on the beat are more vigilant. Murders happen on their own; curfew violations arise when an officer swoops.

The statistics, culled from signal codes that New Orleans Police Department officers assign to reported incidents, are like a tire pressure gauge on a deflated police force, said former city crime analyst Jeff Asher.

With about 1,150 sworn officers — 25 percent fewer than in 2010 — the NOPD has spent relatively little time on proactive patrol work as it scrambles to chase down violence and major property crimes, Asher found.

Whether it’s stopping kids who loiter after hours, keeping an eye out for corner drug buys or spotting reckless motorists, categories of crime that typify self-initiated police work have withered, according to Asher’s review of NOPD calls for service from the start of 2011.

He took special aim at calls for service in which the police response was either “Necessary action taken” or “Report to follow,” categories that tend to indicate an officer-generated look.

“It highlights some of the challenges the manpower issues are creating. These are all measures of pro-activity,” Asher said of the declines. “It’s the difficult choices that the NOPD has largely had to make.”

One could make a case, Asher said, that some of the declines are just as well — perhaps even the result of thoughtful, though unstated policy shifts.

Take curfew violations, which former NOPD Superintendent Ronal Serpas prioritized when he took over as the city’s top cop in 2010. Under Serpas, curfew arrests rose from about 1,400 in 2009 to more than 2,400 in 2010.

In New Orleans, the city’s curfew ordinance says that no one under 17 can be out during school hours, after 9 p.m. in the summer, after 8 p.m. on school nights, after 11 p.m. on Fridays and Saturdays, or after 8 p.m. on any night in the French Quarter.

Several studies have found such enforcement to be ineffective in stalling crime, and in New Orleans, curfew arrests have raised concerns over racial profiling. A report by Nola.com in 2013 found that 93 percent of children who were stopped for violating curfew in the prior four years were black.

Asher measured curfew “incidents,” each of which could produce multiple arrests and send some kids off to the New Orleans Juvenile Curfew Center, operated by Sheriff Marlin Gusman’s office.

His analysis shows a slide from 1,598 curfew incidents in 2011 to 822 in 2013 to an estimated 333 for all of 2015, based on the pace of activity through July 22.

Josh Perry, director of the Louisiana Center for Children’s Rights, said juvenile crime has continued to slide in the city, even as curfew violations have fallen.

“Whether it happened by default or it’s a conscious decision, it is a good idea,” Perry said of fewer curfew violations. “It’s fewer kids who are unnecessarily pushed into the justice system and subjected to the trauma of arrest and sitting in the back of a police car. That’s good for public safety, and good for kids.”

The same might not be said about drunken driving incidents, of which police recorded 1,344 in 2011. If this year’s pace continues, the number for 2015 will be 819, the data show.

The Metropolitan Crime Commission reached a similar conclusion about the effect of the NOPD’s manpower decline in a report this year that focused on reductions in felony drug busts and a nosedive in arrests for driving with a suspended license or without a license — the fallout of a stripped-down Traffic Division.

Inspector General Ed Quatrevaux’s office, meanwhile, found last year that only a fraction of the sworn NOPD force — 30 percent — is assigned to regular platoon shifts, and just one in five sworn officers was assigned to answer calls for service.

NOPD Superintendent Michael Harrison , in an interview last week, didn’t dispute the drop-off in proactive policing amid a stubborn manpower shortfall that dates back to an NOPD hiring freeze from five years ago.

NOPD spokesman Tyler Gamble pointed to successes with the NOPD’s focus on the city’s rampant violent crime problem, as well as proactive patrols it does conduct and efforts to obey a federal consent decree. Gamble cited figures showing 1,021 guns taken off the street so far this year, compared with 936 over the same period last year.

Violent felony arrests also are up, Gamble noted, citing a Crime Commission report.

He also said the federally mandated reforms require “extensive documentation and clear justification for all officer-initiated citizen stops.” That paperwork, Gamble said, has significantly impacted officer-initiated stops, particularly for curfew violations and suspicious persons.

Harrison last week said he sees a few bright spots in hiring more officers and making better use of the ones who already don a badge and body camera.

For those who need non-emergency police help, some relief is on the way, Harrison said. The department is slated to go live within a few months with an online system for reporting minor thefts and other non-emergency incidents, aiming to take a load off the 911 dispatch system.

Harrison said he’s also worked to give commanders in the eight police districts more flexibility, moving work away from patrol officers to free them up.

“It’s about being smart and efficient,” he said. “Having fewer officers and having to rebuild the department ... takes a lot of time.”

Harrison said he also hopes later to convince U.S. District Judge Susie Morgan, who is overseeing the reforms mandated under the consent decree, to increase the allowable size of police academy classes.

For a second straight year, the Landrieu administration has fallen behind in fulfilling its stated plan to field five police academy classes with as many as 150 recruits. That goal won’t likely be reached by year’s end.

Follow John Simerman on Twitter, @johnsimerman.