Mayor Bloomberg announced today that New York’s graduation rates are on the rise for the seventh consecutive year.

According to Department of Education data the city’s four-year graduation rate climbed from nearly 53 percent in 2007 to over 56 percent in 2008. The nearly 4-percentage point jump refers to students who started ninth grade in 2004 and graduated in 2008.

The percentage of students graduating from the city’s public schools fell short of the statewide average of roughly 71 percent. But New York City’s rates were higher compared to those in major cities like Buffalo and Syracuse.

Calling the rate increase “dramatic,” Mayor Bloomberg declared it a victory for the 2002 law that centralized the city’s school governance. The law is set to sunset on June 30.

“The bottom line is, all signs are pointing in the right direction,” Bloomberg said. “And I think everybody understands that mayoral control really has been the key to all of this.”

He added that between 1992 and 2002, the city never saw more than roughly half of its students graduate, whereas in the last seven years graduation rates have increased significantly. Critics of mayoral control have argued that, when it comes to test scores, notable increases began four years before Bloomberg took office. Others have reported that students the city labels as “discharges” may actually be drop-outs, contributing to the city’s lowered drop-out rates.

The most remarkable increase came in the form of a 10-percentage point boost for the city’s English Language Learners — students who are still learning English. In 2008, the graduation rate for these students was about 36 percent, up from 25 percent in 2007. Schools chancellor Joel Klein attributed this jump to the growth of small schools that cater to ELL students.

Both the mayor and Klein emphasized that not only were more students graduating on time, but a slightly higher percentage were earning Regents diplomas, which require students to meet higher standards than a local diploma.

“This year our entire gain was in Regents diplomas,” Klein said, adding that the 4-point bump was composed entirely of students who had earned Regents diplomas.

Pointing to a chart showing the graduation rates of the city’s black and Hispanic students next to those of white and Asian students, Bloomberg declared it “the most encouraging chart of all.”

In 2008, roughly 49 percent of Hispanic students graduated in four years, as did more than 51 percent of black students. That’s compared to roughly 74 percent of Asian students and 72 percent of white students.

For the last four years, the city has followed the state’s formula for measuring graduation rates by excluding students who get GEDs and special education diplomas rather than local or Regents diplomas. The state’s data also incorporates students who complete summer school, allowing them to graduate in August rather than in May. With this last cohort of students added on, the city’s four-year graduation rate for 2008 reaches 60.7 percent.

Reminding his audience of journalists that students’ math and English scores were up, Bloomberg said that next year’s graduation rates would be “even more impressive because many of the kids are going to be in high school.”