Sixteen months ago, Mayor Rahm Emanuel set a high bar for his new City Colleges chancellor Juan Salgado: a 25 percent graduation rate by 2019 in a system that, not too long ago, graduated just 7 percent of its students.

Now, the mayor and Salgado are claiming to be within striking distance of that ambitious goal with a graduation rate of 22.9 percent.

But the veracity of their claim is being called in question by a series of investigations over the years that have accused the system of inflating graduation rates.

Last fall, an investigation by the Better Government Association concluded that City Colleges issued thousands of degrees after lowering credit-hours requirements and diluting education standards.

Math requirements were eliminated altogether. The number of credit hours required to complete general education course requirements were reduced from 30 to 20. Classroom credit hours required to secure degrees were reduced from 21 hours to 15 hours, the investigation concluded.

The BGA also concluded that more than 2,800 City Colleges degrees were belatedly and mysteriously issued to students long gone from the system. Known as “automated conferral,” the program sent degrees to students, some of whom had not attended City Colleges in a “year or even decades,” the investigation concluded.

With that dark cloud still hanging over the system’s head, it’s no wonder that Tony Johnston, president of the Cook County Colleges Teachers Union, has trouble believing that the new graduation rate is really 22.9 percent.

“I would be very wary about this … based on past issues with transparency of graduation rates. We need to be suspicious and take a hard look at what they’re saying the rates are and see if it’s actually true,” said Johnston, who represents nearly 600 full-time faculty members.

“A lot of the graduation rates were inflated. A lot of these certificates were … basically terminal degrees. They were awarded without the student even knowing about them. And they were done to make the numbers look better than they really were. I find it difficult to believe that we would go from where we were previously to 22.9 percent largely driven by … the Star Scholarship awardees.”

Salgado bristled at the suggestion that the numbers he and the mayor are so proud of weren’t real.

The chancellor did not respond when asked repeatedly whether graduation rates were ever inflated, fudged or pumped up by lower standards. But he emphatically insisted that it’s not happening now.

“I’m here as of a year ago. And I can tell you I stand behind these numbers. I’m happy to sit down with anybody to review them in detail. It’s rock-solid. … These are real results. … I stand behind these numbers. I’m willing to share them with any stakeholder in great detail … to understand that the numbers we’re producing are absolutely accurate,” Salgado said.

“Our curriculum is rigorous. You can go out and talk to our employer partners,” he said. “This is why they’re hiring our students because it’s never been more rigorous than it is today. You can look at our practices and they are best practices. … What’s driving this grad rate increase is the earning of associates degrees.”

The increase — from 18 percent a year ago — was also driven in part by a 47 percent graduation rate among recipients of the Chicago Star Scholarship that offers free City Colleges tuition to Chicago Public School students who maintain a B average.

Emanuel rolled out the Star Scholarship program on the eve of his 2015 re-election bid. It has since benefitted 4,500 CPS graduates from 75 different ZIP codes and more than 200 different high schools.

Together, they have earned more than $3 million in scholarship offers from four-year colleges and universities that have forged partnerships with City Colleges.

Emanuel said the “record-breaking” graduation rate “makes it clear that, when we provide our students with the resources and pathways they need to succeed, there is no limit” to what they can achieve.

“This is more than just a statistic. It’s a record number of students leaving City Colleges with a career path and the opportunity for a bright future. That’s what this is about,” the mayor said.

“We’ve long had Star Scholar-like students in our colleges. The difference here is that these students are now being supported financially, in addition to all of the other supports we’re providing,” Salgado said.

“When we can keep the cost of our education affordable — or in this case, they earn the opportunity for the scholarship — and provide the requisite supports, our students succeed. That’s what we’re learning from our Star Scholars as well as from our general population of students.”

Arguing that “nothing comes easy” to City Colleges students, many of whom work part-time, Salgado pointed to an array of student support services he has put in place to help them succeed.

That includes a lower student-to-adviser ratio.

Technology programming will also be expanded to include nine “boot camps” in cyber-security and coding across five campuses by the end of this year.

“We have wellness centers, tutoring centers, disability-access centers. We have math emporiums. We have veterans services. We have a suite of supports advising so our students are taking the right courses. It’s that suite of supports that ensures that our students do well,” he said.

During a luncheon address to the City Club of Chicago last month, Salgado set another high bar for himself: To have at least 50 percent of City Colleges graduates have “work-based learning opportunities” — either before they graduate or immediately after.

“We’ve seen it. When we put the supports in place and we open doors of opportunity, our students do very well,” he said.