Chicago (CNN) It seemed a typical month in the nation's third largest city.

A 15-year-old boy returning home from a elite Chicago prep school suffered a graze wound to the head early last month when a stray bullet pierced the window of a city bus, police said.

An agent with the US Bureau of Alcohol, Tobacco and Firearms was shot in the face while working on a newly created task force combating gun trafficking.

The mother of a 19-year-old college student made an emotional appeal for a citywide ceasefire on Mother's Day weekend after her daughter was shot at a party.

"This is a Trump-free zone," Mayor Rahm Emanuel told CNN this week. "We have facts. What matters ... is what happens on the street."

The city has had 52 fewer murders and 229 fewer shootings through the end of May -- a 21% drop in both categories -- compared to the first five months of 2017, according to the Chicago Police Department.

May alone saw a 21% decline in murders compared to last year -- from 58 to 46 -- along with a 5% drop in shooting incidents, police said.

So far this year, Chicago has had 500 fewer shooting victims than the same period in 2016, police said.

"The truth of the matter is, if you feel comfortable, you're going to be outside," Emanuel said. "If you're not comfortable, you're going pull the kids in off the porch inside. It's not a statistic. It's a feeling towards that."

City mobilizes in response to gun violence

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The city has made considerable gains over the past year. It saw a 16% drop in murders from 2016 -- the deadliest year in nearly two decades, with 771 murders -- to 2017, when there were 650.

"We're making progress, " Emanuel said. "We're not where we need to be but (what) we do have is a strategy that generally people buy into."

City officials attribute the declines to the hiring of more officers, stronger community policing efforts and investments in technology, such as ShotSpotter gunshot detection systems and predictive crime software that helps deploy officers.

"ShotSpotter is probably key to that to what we're doing here," the department's No. 2 man, First Deputy Superintendent Anthony Riccio, said of technology that detects gunfire and often notifies officers before 911 is called.

"Officers get that notification right away to cell phones that they have in their cars and they're able to respond to those areas."

Patrick Sharkey, an NYU professor and author of "Uneasy Peace: The Great Crime Decline, the Renewal of City Life, and the Next War on Violence," said Chicago has mobilized in response to a spike in violent crime like no other in the country.

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"Leaders throughout the city have come together in a way that is very unique, and the common goal has been to fight back against the surge of gun violence," he said.

"The police department has shown a willingness to change how it interacts with residents, and it has been helped in this effort by foundations."

'Statistics disguise untold human suffering'

The Cure Violence organization, which takes a public-health approach to violence prevention, and other groups have been dispatching "violence interrupters" to the roughest neighborhoods to intervene in gang conflicts before they escalate, according to Gary Slutkin, the organization's founder and executive director.

More than 150 outreach workers -- some of them former gang members -- stay in touch with friends and relatives of shooting victims in an attempt to prevent retaliation, he said.

"Violence is unpredictable, and none of this guarantees that it will continue to fall," Sharkey said of the anti-gun violence efforts.

"But the change over the past year or so is very real, and reflects a citywide commitment to confront the recent rise in violent crime."

While the data suggest a downward trend in both murders and shootings, crime tends to pick up with warmer weather, said Arthur Lurigio, a professor of psychology and criminal justice at Loyola University Chicago.

"If this trend continues until Labor Day, Chicago might be on its way to a year with 500 or fewer homicides, which is closer to the normative number of murders in recent history, beginning in 2004 and factoring out 2016 and 2017 as aberrations," he said.

Still, Lurigio said the promising statistics disguise the untold human suffering that accompanies every casualty.

"Shootings can leave victims with permanent physical and emotional disabilities, including symptoms of post-traumatic stress disorder and traumatic brain injury," he said.

"The survivors of homicide never move on completely from their devastating loses. Bullets in the air leave permanent pain in the heart and create ripples of sorrow in families and communities that affect generations to come."

'They're shooting in broad daylight'

Michael Frederick, a longtime South Side resident, said the gun violence near his store shows no sign of abating.

"You tend to want to stay in your house because there's so much shooting going on," he said.

"They're shooting in broad daylight. They don't save it for the nighttime."

As Imani Williams, a College of DuPage freshman, recovered from a gunshot in early May, her mother appealed for a Mother's Day ceasefire, CNN affiliate WLS-TV reported.

"I'm going to have a nice Mother's Day because my daughter is alive and I celebrate her," LaShawn Allen said. "A lot of mothers don't get this opportunity."

The ATF agent shot in the face in Chicago's Back of the Yards neighborhood last month was the fourth law enforcement officer shot in the past year, the station reported.

When the 15-year-old boy was grazed in the head by a bullet on his way home from school on May 2, Chicago Police Superintendent Eddie Johnson said officers responded after ShotSpotter technology picked up the gunfire, according to WLS-TV

"It infuriates me that we have a good kid doing what we all expect him to do, and he's a victim of something like this," Johnson told reporters.

The stray bullet, from a shooting one block away, hit Ulises Triano. He thought it was a lighting strike until blood streamed down his head.

Said Emanuel, "The real test is, when kids are going to school, are they thinking of their safety or their studies? That's how we measure success."