About 21 percent of the city’s middle- and high-schoolers attend schools in the Bronx. But 48 percent of the summonses that police handed out in schools last year went to Bronx students.

That is one statistic about policing in city schools that the New York Civil Liberties Union is highlighting now that it has a full year of school policing data in hand. Since last year, the New York Police Department has been required to publish information every three months about arrests it has made and summonses it has issued in schools, where it has more than 5,000 officers assigned.

Between July 1, 2011, and June 30, 2012, police officers made 882 arrests in city schools and issued 1,666 summonses for behavior, according to the NYCLU’s tally of the year’s data.

Virtually all of the arrests — more than 95 percent — were for black and Latino students, who make up about 70 percent of the city’s enrollment. Three quarters were of male students. And 20 percent were of students between the ages of 11 and 14.

Two-thirds of the summonses were issued for “disorderly behavior,” a category of offense that the NYLCU argues usually amounts to typical teenaged behavior. Those behaviors are best dealt with by educators, not by directing students into the criminal justice system, the group argues.

The group wants to see the number of police officers reduced and more authority over discipline restored to teachers and principals.

But the Department of Education has steadfastly maintained that its policing practices should not be changed because major crime has dropped, an argument that the NYPD has used recently to defend its controversial “stop and frisk” policy.

“In the last 10 years, we’ve reduced major crimes committed in schools by 49 percent and violent crime by 45 percent, while still maintaining one of the lowest rates of school-based arrests for any major district in the country,” said Marge Feinberg, a department spokeswoman, in a statement.

In a statement, the NYCLU’s executive director, Donna Lieberman, said the school policing statistics are setting up the city’s Young Men’s Initiative to fail. Mayor Bloomberg announced the initiative, which includes a number of programs aimed at helping poor black and Latino men, last year.

“If the Bloomberg administration is serious about helping young men of color succeed, then it must address these disparities and focus more resources on educating children, not arresting them,” Lieberman said.

Since 1998, NYPD has been authorized to provide law enforcement inside city schools, but the department’s repeated refusals to release arrest information to the public led civil rights groups, including the NYCLU, to push for the Student Safety Act. The City Council passed the act in 2010, requiring both the NYPD and Department of Education to release more data about policing inside schools. According to the education department’s data, suspensions also go most often to black and Latino boys.