Mayor Michael Bloomberg defended the small dip in the city's graduation rate as "amazing" given the state's recent push to make it harder for students to graduate.

"You could say it's flattened out, but remember each year the standards have gone up," the mayor said at a press conference in the Department of Education's headquarters on Monday.

New York City's four-your graduation rate fell from 60.9 percent in 2011 to 60.4 percent last year. That was for students who completed high school in June; it fell from 65.5 percent to 64.7 percent when adding in August graduates.

For years, the mayor has proudly trumpeted the city's progress in raising its graduation rate -- which was less than 50 percent when he took office in 2002. So it was a challenge for him to defend a decline in those numbers for the first time during his 12-year tenure.

"This is improved performance," he said, with more than a touch of exasperation. "Yes, the nominal number is down but the standards were so much higher you're comparing apples to oranges."

Last year was the first time that the state required all students to score at least the 65 on five Regents exams in order to graduate; previously they were allowed to score 55 on some of the tests. The state eliminated the so-called "Local diploma" for everyone except students with special needs.

Schools Chancellor Dennis Walcott found a silver lining in the declining dropout rate which is now at about 12 percent for New York City high school students.

Walcott also noted that the achievement gap between black and Hispanic students and whites shrank over time, although the graduation rate for white students remains more than 20 percentage points higher.

New York City students still learning English saw their graduation rate drop by about four percentage points, to 35.4 percent, reflecting a statewide trend. Chief Academic Officer Shael Polakow-Suransky said that's likely a result of raising the passing score to 65 on the Regents exams.

"For the first time the kids had to take the English Regents or the Global Regents and get a 65 on it," he said, adding "that extra 10 point requirement hurt a lot of kids."

He said the city has pledged over $4 million in grants and city funds to help 25 schools with the weakest graduation rates for English Language learners to partner with schools that have done a better job.

The state's push to raise standards includes a measurement of “aspirational performance" which helps predict college and career readiness. Students need to score at least a 75 on their English Regents and an 80 on their math Regents to meet this criteria, recognition that these are the minimum scores needed to pass freshman college courses or to compete in the job market.

There was a slight uptick in the percentage of New York City students deemed ready for college and careers, according to 2012 state figures: 21.9 percent compared to 20.7 percent the previous year.

But, once again, black and Hispanic students had much lower college readiness rates than whites and Asians.

Philip Weinberg, principal of the High School of Telecommunication Arts and Technology in Brooklyn, acknowledged that the standards are definitely harder. "It's difficult convincing a kid, yes 65 is the grade you need to pass but you really need 80."

His school's four-year graduation rate rose last year to almost 83 percent, an increase of more than four percentage points. Weinberg said he and his staff encouraged students to take their Regents exams earlier, so they could take them again later on if they didn't pass or wanted a higher score.

For Bloomberg, who made education reform a hallmark of his administration, the graduation rates data could be seen as a test of his legacy. He encouraged the next mayor to continue his reforms.

"We would just become the laughingstock of the rest of the country if you were to roll back everything that has worked so well," he said. He singled out the teachers union for its efforts over the years to prevent the closing of low-performing high schools, a strategy he sees as a big factor in the city's improved graduation rates.