For the first time since Mayor Michael Bloomberg took office, the city's high school graduation rates fell slightly for students who graduate both in June and August.
State officials say the city's rate for on-time graduations declined a half of a percentage point from 60.9 percent in 2011 to 60.4 percent in 2012.
The statewide rate remained flat at 74 percent.
The graduation rates for students who graduate in August, using the summer to meet diploma requirements, also fell slightly from 65.5 percent to 64.7 percent.
Mayor Michael Bloomberg has pointed to improvements in the graduation rate as the chief evidence that his school reforms are working.
However, he has warned that higher graduation standards could make it more difficult for students to finish.
For the first time this year, the state is no longer allowing students to graduate with a local diploma, which granted a diploma with students with lower Regents scores.
The mayor and Schools Chancellor Dennis Walcott told reporters Monday that the Department Of Education is not in decline.
"The standards are going up. The state wants to raise them, we've always been in favor of raising them. The standards the marketplace is requiring keep going up," Bloomberg said. "This is showing improvement, not decline, no matter how you want to spell it."
"So the reality is, I would rather have our students in school and meeting a higher bar in graduating and preparing them for college and careers than the standard that existed before when they were graduating," Walcott said.
The graduation rate is still about 14 percentage points higher than it was in 2005.
Bloomberg said he has set an example in the long-term.
"Why would any rational person want to roll it back? [Education Secretary] Arne Duncan, the president, everyone thinks we have done exactly the right thing," the mayor said.
But some eyeing his job say Bloomberg's years will be remembered for shuttering schools, standardized tests and an icy relationship with the United Federation of Teachers.
Bloomberg also took the opportunity to blast the city's teachers union, offering a warning to his potential successor if he or she was looking for its endorsement.
"It's almost the kiss of death. And maybe I don't know what goes through people's minds, but if the UFT wants it, it ain't good and you don't want that person," Bloomberg said.