This from the U.S. Department of Justice's Bureau of Justice Statistics' handy new tool. For prisoners released after serving state prison time for drug possession or trafficking:
70.6% were arrested for new crime within 3 years of release.
45.8% were adjudicated (or brought to court) for a new crime within 2 years.
24.0% were convicted for a new crime within one year.
8.0% were reincarcerated (i.e. placed in jail or prison) following a conviction on a new crime within 6 months.
27.8% were convicted of a new crime and placed in prison within 3 years.
Also: The latest infographic on the medical marijuana industry. (click to zoom)