The national juvenile arrest rate peaked in 1996 and has since been on a steady, and in some years sharp, decline.
Between 2006 and 2015, the number of arrests fell 55 percent in the country as a whole and 49 percent here in Arizona.
Christopher Vogler, who works with the Pima County Juvenile Court, said the same has been true locally.
"Law enforcement agencies and justice agencies have worked hard to start seeing teenage behavior as teenage behavior and not necessarily as criminal behavior," he said.
But that falls short of explaining the drop. The approach has not been adopted universally, he said, and yet still crime has fallen.
Vogler said the steep decline in juvenile crime has leveled off a bit in recent years but is still trending down.