SACRAMENTO, Calif. (AP) – A new study by an advocacy group says a voter-approved initiative has cut California’s prison and jail populations by about 13,000 inmates.

Voters approved Proposition 47 a year ago to reduce penalties for some drug and property crimes.

Stanford Law School’s Justice Advocacy Project helped write Proposition 47. It says in a report Thursday that because of the initiative, the number of jail inmates released early due to overcrowding was cut by 35 percent.

Stanford says the measure saved the state about $150 million this year and saved counties more than $200 million.

It says corrections department data shows fewer than 5 percent of state inmates released early under Proposition 47 have been convicted of new crimes and sent back to prison.

Law enforcement officials continue to raise concerns.

Copyright 2015 The Associated Press.