More than two-thirds of paroled inmates in California are back in prison within three years, with the highest rates among younger inmates and those with shorter sentences, according to a new state report.

The recidivism rate in California remains among the nation's highest. But the report by the Department of Corrections and Rehabilitation, released Tuesday, cited a small decline in the rate of imprisonment within a year of release - from 49.1 percent in 2005-06 to 47.5 percent in 2007-08.

"These results are very encouraging" and reflect Gov. Arnold Schwarzenegger's commitment to rehabilitation, said department Secretary Matthew Cate.

Assistant Secretary Steven Chapman said the 1.6 percentage point decline reflected a reduction of thousands of crimes.

The report also found, however, that the three-year recidivism rate increased slightly: 67.5 percent of those released in 2005-06 returned to prison in the next three years, compared with 66.2 percent of those paroled three years earlier.

About 70 percent of the new imprisonments were for parole violations rather than criminal convictions, the report found.

Schwarzenegger has proposed to reduce re-imprisonment for minor parole violations as a cost-saving measure. But he also cut spending on prison rehabilitation programs in the current state budget.

The report also found that:

-- The highest recidivism rate, almost 75 percent over three years, was for parolees ages 24 or younger. The rate for parolees 60 or older was 46 percent.

-- Women, who made up one-tenth of the parolees, were 15 percent less likely to return to prison than men.

-- The re-imprisonment rate was highest among those who had been paroled after serving 19 to 24 months in prison and was lowest for those who had served more than 15 years.

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The report can be read at links.sfgate.com/ZKNN.