Within two years, homicides had dropped by nearly a quarter and shootings by more than 15 percent.

But the flush of early success has since been tempered by the city's toughest streets, where violent crime has proven once again to be deeply rooted.

Progress in recent years has been more incremental. And with homicides - the most closely watched barometer of crime - ground has been lost.

When 2012 comes to a close, killings will have risen for the third straight year, the highest total in Nutter's five years in office. The count was 337 as of Monday afternoon, up from 324 in 2011.

Aggravated assaults with a gun (more than 2,400) will have stayed the same, while robberies with a gun (more than 3,300) will have dropped slightly from 2011.

There is good news: overall crime is down more than 3 percent this year, and 9 percent since Nutter took office.

And violent crime, despite the uptick in killings, has dropped more than 15 percent from 2007. The number of people injured or killed by gunfire is down 20 percent since then.

Nutter called the numbers "still unacceptable."

"I'm proud of the success, appreciate all the effort," he said. "I think we can do better."

In an interview in his office last week, Nutter was pragmatic about the city's challenges without giving up hope of a paradigm-shifting change on a par with the historic crime drops in New York City and Washington.

"I am the most practical, realistic, yet optimistic person that you're going to find," he said. "This is my hometown. I have no reason to believe . . . that Philadelphians are any more prone to violence than most other Americans."

The experience of other large cities in 2012 has varied. New York and Washington will log their fewest killings in a half-century.

Homicides in Chicago, meanwhile, reached 500 on Friday, a 15 percent increase from last year.

While many factors have played a role in New York's lauded turnaround, Nutter noted that New York state has some of the nation's toughest gun laws.

"The biggest challenge in this city is the overwhelming proliferation and accessibility of guns," he said.

Nutter said he would unveil "thoughts and ideas" in January on how to combat gun violence locally and nationally. Although he refused to elaborate, the mayor, who last week mocked the National Rifle Association on national television, seemed ready to wade again into the gun-control debate.

"Your right to have a gun should not interfere with my right to be safe," he said. "The question is what kinds of guns and who can have them. It's a longer, broader conversation."

Police Commissioner Charles H. Ramsey, who was named to a gun policy task force headed by Vice President Biden, said only so much progress can be made without federal leadership - 85 percent of the city's 2012 homicides were committed with a firearm, the most popular being the semiautomatic 9mm handgun. That percentage has risen gradually from 48 percent over the last quarter-century.

Ramsey said he hoped the sense of urgency after the school massacre in Newtown, Conn., doesn't fade with time and political pressure.

"If 330 murders doesn't count as mass murder, I don't know what is," he said. "We only wake up for a brief moment in time and then we fall back to sleep. It's not going to correct itself."

Ramsey also said that a midyear review of the city's shooting victims showed those hit multiple times had risen 30 percent and victims shot in the head was up 11 percent. That could explain why shootings overall are down but killings are up.

"It tells us the intent is definitely to kill," he said.

As in most cities, homicides here have dropped significantly since the years following the arrival of crack cocaine - Philadelphia's record was set in 1990, with 497 homicides.

"We're very quick to forget exactly the progress that's been made," Ramsey said. "Short-term, you're always up against last year's numbers. I would hope we would eventually look at trends as opposed to year-to-year numbers."

He acknowledged that having fewer than 300 homicides - something that hasn't happened here since 2002 - is a psychological barrier for the city.

Ramsey was police chief in Washington for nine years, when homicides in the city fell below 200 - a previously unthinkable accomplishment.

The capital's 2012 homicide total is not expected to reach 100. Ramsey said similar success was possible here.

"I think we can get below 200 in this city," he said. "When I said I thought we could get below 100 murders in D.C., people looked at me like I was crazy."

Ramsey also noted that Washington's progress was accompanied by seismic economic and demographic shifts in the district.

Nutter, too, says the underlying social causes of crime - such as school dropout rates and unemployment - ultimately have to be addressed.

"I give a half a dozen to 10 speeches a day. Somewhere in almost every one of them, I'm talking about education," he said. "The reason? It's about crime. Better-educated public, more people working, less crime."

The city's economic data - like its crime figures - remain daunting, even though the city weathered the recession without disaster.

Philadelphia's poverty rate rose to 28.4 percent in 2011, with nearly 40 percent of children living in poverty, according to the U.S. census. Of major cities, only Detroit had a median household income less than Philadelphia's $34,207.

Meanwhile, unemployment has continued to hover in double digits in Philadelphia - 10.8 percent in November, according to the federal Bureau of Labor Statistics.

In the African American community, the numbers are starker. About half the city's black men are jobless, said Bilal Qayyum, a longtime activist and president of the Father's Day Rally Committee.

"We're never going to eliminate crime, but you decrease it by providing opportunity, particularly with men," he said. "We really have to talk about how we create jobs."

Nutter and Ramsey say police tactics have made a dent. They credited several programs with tamping down violent crime in the second half of the year. Those include GunStat, which tracks violent offenders in targeted areas, and a policy of seeking high bail in gun crimes.

After two years of tight budgets, the police academy graduated two classes this year with a third on its way, putting 120 new officers on the street.

While the ultimate answer may be making fundamental social changes, Nutter said, "we still have to patrol these streets every day."

"It is unacceptable for anyone to ever think we can't do something better, something more," he said. "Anyone who's thinking that - at least if they're in public service - they need to find another job."