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.

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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.

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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.

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Copyright 2015 The Associated Press.