[O]nly 23 percent of students in New York City graduated ready for college or careers in 2009, not counting special-education students.

In the wealthier districts across the state, the news is better: 72 percent of students in “low need” districts are graduating ready for college or careers. But even that is well under the 95 percent of students in those districts who are now graduating.

The data also cast new doubt on the ability of charter schools to outperform their traditional school peers. Statewide, only 10 percent of students at charters graduated in 2009 at college-ready standards, though 49 percent received diplomas.