SAN JOSE -- Despite efforts to hire and retain officers, officials say that if current trends continue, over the next two years the San Jose Police Department will shrink to two-thirds its size in 2008, when budget reduction measures sparked a running exodus of officers.

Worsening the bleak projection from the department are estimates that nearly half of the most recent police academy graduates -- considered to be the backbone of any replenishment plan -- have left for other agencies and that the department could reasonably expect just a quarter to actually stay on.

According to the projections, by June 2016, the department will have 879 street-ready officers, though police insiders say the number ready to deploy would be closer to 800 to account for ongoing disability, injuries and military leave.

Currently, the police department has 970 street-ready officers and is deploying 906, a far cry from the nearly 1,400 street-ready officers -- of which more than 1,200 were in the field -- six years ago, at the start of a series of budget cuts and ensuing pension reforms that led to layoffs, early retirements and resignations from the department.

A package of city efforts to offset the departures -- which include restoring officers' pay to 2009 levels and restoring police academies after a three-year hiatus -- appear to have only slowed the losses at best, since the 2016 estimate reflects a loss of 50 officers a year. Over the past three years, SJPD has seen at least 100 officers leave annually.

The San Jose Police Officers Association and the San Jose Fire Fighters Local 230 discussed the projections and painted a dire public-safety picture at a Willow Glen public forum Thursday evening.

"San Jose citizens have been promised an additional 200 officers on the streets in two years," said Officer James Gonzales, referring to a plan drafted by the mayor and Councilman Sam Liccardo last summer. "It's important that people know that's not going to happen."

The city's plans to add officers could be moot if pay, pension and disability benefits continue to be outpaced by surrounding Bay Area agencies, which have made SJPD less competitive for high-quality recruits.

Gonzales' presentation in Willow Glen stated that retirements and officers leaving for other departments outpace the number of new officers who can be trained through police academy, even if they stick around.

David Vossbrink, the city spokesman, acknowledged that the current trend lines, if not altered, could reach the department's projections. But the city expects much will change over the next two years -- and is working hard to ensure that the department can retain officers.

"Rather than focusing on a potential number itself, we are focusing on making changes that will help the situation," Vossbrink wrote in an email. "Retention is a critical priority for SJPD and the City, and we are addressing key factors for keeping and attracting officers."

But of the fall 2013 graduating class, which was the first to be hired under a reduced pension plan, 22 of 40 rookie officers remain with the department. Sources say of the 22, at least half are being backgrounded by other police agencies for potential hiring, and even more are looking elsewhere.

Gonzales said that shows that even the city's estimate is "very conservative."Vice Mayor Madison Nguyen, who is a candidate for mayor, insists the city now is positioned to hire more officers.

"We have more money in the general fund today to hire officers, and that's exactly what we intend to do," Nguyen said.

She added that the city receives "hundreds and hundreds" of applications from prospective recruits who believe San Jose is a good place for a law-enforcement career.

"It's very unfortunate that the police union continues to do this, spinning information out of control," Nguyen said. "This is just the same thing that they have been doing over and over."

In a statement emailed Thursday, Mayor Chuck Reed said the reason for the shrinkage in police and fire departments is due to retirement costs. He said that despite increasing the police department budget by nearly $100 million over the past 10 years, there are fewer officers because those funds have gone to retirement costs.

"And if we had not adopted fiscal reforms during the past few years, we'd have even fewer police officers and firefighters than we do today," Reed stated.

Police union president Sgt. Jim Unland said the current state of pay and benefits are the primary culprit for the department's troubles with hiring and retention. To gain even baseline competitiveness with other departments, he said, the city has to adopt a policy more in line with statewide levels.

"Unless they move pretty damn quickly, I don't know what happens," Unland said.

Reed said they have taken steps to retain officers such as restoring pay by 10 percent and clarifying disability provisions. He added that the police union has undermined such efforts by encouraging veteran officers to resign, retire or go to other agencies as well as encouraged new recruits to go to other cities after graduating from San Jose's police academy.

Gonzales concluded the Willow Glen meeting by telling residents it will be up to them to undo the damage done by Measure B, a voter-approved measure which reduced pensions and changed disability benefits for public safety workers.

"It can be fixed. We can make San Jose competitive," he said. "Gimmicks won't address crime. The only thing that can be done is to fix the flaws in Measure B."

Mercury News staff writers Mark Emmons and Eric Kurhi contributed to this report. Contact Robert Salonga at 408-920-5002. Follow him at Twitter.com/robertsalonga.