Just over three years after Multnomah County prosecutors started diverting teens convicted of eligible Measure 11 crimes from prison sentences to probation, the percentage of teens going to prison on these charges has decreased sharply.

This week, the Multnomah County District Attorney's Office released an analysis of court records looking back at the last three years of eligible juvenile cases involving these crimes.

The eligible crimes include second-degree assault, kidnapping and robbery—each of which comes with a presumptive prison sentence of five years and ten months.

Before the Juvenile Justice Reinvestment Program began in mid-2013, nearly 69 percent of teens convicted of these crimes went to prison. Three years later, 82 percent get probation instead.

The findings are a small sample size.

Only 21 teenagers have been deemed eligible for the program—but they are a highly vulnerable group of children that Multnomah County prosecutors would rather not send to prison.

Measure 11's minimum sentencing guidelines apply to anyone over the age of 15, but Multnomah County District Attorney Rod Underhill adopted a county-wide policy of offering 15- to 17-year-old defendants a chance to take a plea deal in juvenile court rather than adult court.

In 2014, he extended an offer to give a "second look" at the case of anyone serving prison sentences because of a conviction for one of the eligible crimes when they were a juvenile—those individuals could be released early.

The three-year study of the juvenile justice reinvestment program did find some disappointing trends in the court data. Dramatic racial disparities among the teenagers convicted of the eligible crimes remained consistent before and after the DA started offering juvenile plea deals for probation instead of adult prison sentences. Among the teens eligible for the program, more than half were black and a third were Latino.

That disparity carried over into the 18 percent of teens who still had to serve prison time: five were black, four were Latino and only two were white.