Mayor Bill de Blasio announced on Tuesday that this past school year was the safest for New York City public schools since the Police Department began tracking schools data in 1998, a drop in crime that tracks that of the city overall.

“The 2016-2017 school year was the safest on record in the history of New York City,” Mr. de Blasio said at Middle School 88, the Peter Rouget school in Sunset Park, Brooklyn, where he was flanked by Carmen Fariña, the city schools chancellor, and James P. O’Neill, the police commissioner. “Everyone should be proud of that.”

The Police Department said that arrests fell 8 percent this past school year and summonses dropped by 11 percent. The number of major crimes reported, such as grand larceny and felony assault, also fell from 532 in the 2015-16 school year to 503 in the 2016-17 school year. The city has about 1,800 public schools.

Additionally, Mr. de Blasio said, just two city schools remained on the “persistently dangerous” list, a designation the federal government requires states to make. Just two years ago, there had been 27 city schools in that category. The designation is made using data from a state system called Violent and Disruptive Incident Reporting, or Vadir. Vadir data has not yet been released for the 2016-17 school year.