The price of less crowded California prisons? It’s a 9 percent increase in crimes such as car burglaries, shoplifting, auto burglary, identity theft, and other transgressions victimizing law-abiding Californians.

The nonpartisan Public Policy Institute of California’s research determined larcenies were up 9 percent in 2016. That translates into 135 more thefts per 100,000 residents before voter approved Proposition 47 reduced the consequences for a number of crimes that once were classified as felonies. The bottom line of the research — reduced criminal penalties have led to more thefts.

That’s contrary to what many proponents contended would happen if Prop. 47 passed.

Auto burglary, as an example, has skyrocketed in Manteca since Prop. 47 passed.

In 2014 — the year voters approve the ballot measure and before it was implemented — Manteca had 344 auto burglaries. They soared to 554 in 2016. So far this year the pace of auto burglaries is down 9.44 percent in comparing criminal activity for the January and April for 2017 and 2018.

Misdemeanor thefts in Manteca that include many of the crimes that were formerly felonies through the first four months of this year are up 15.6 percent going from 250 in January through April 2016 to 289 for the same four months of this year.

Meanwhile Part 1 crimes — 12 categories of felony crimes that often included violence and are monitored by the FBI to keep a pulse on the nation’s crime trends — are for the most part dropping. Vehicle theft, as an example, so far this year is down 11.78 percent going from 365 to 322. That follows the general state trends and re-enforces the Public Policy Institute of California’s research.

The ballot measure dropped felony status for a number of crimes that once could lead to prison terms but are now misdemeanors that often bring minimal jail sentences.

Researchers verified Prop. 47 can be blamed for more theft but at the same time determined it did not lead to and of California’s increase in violent crime.

Maximum jail sentences allowed under law now for auto burglaries and such are rarely served the length of time they are imposed. That’s because of the prison realignment imposed by Sacramento that sent a number of non-violent felons to serve time in county jails to meet court-order prison capacity marks. That has made less room in jail for those convicted of crimes such as auto burglaries.

Researchers compared California's crime trends to those in other states with historically similar trends. They found the increase in California's violent crime rate was less than that of comparison states, but larcenies jumped in California as they declined elsewhere.

California still has historically low crime rates despite recent changes in the criminal justice system aimed at reducing mass incarceration and increasing rehabilitation and treatment programs, said Lenore Anderson, executive director of Californians for Safety and Justice, who led the drive to pass Proposition 47.

"This report shows we are making progress," she said in a statement calling for less spending on prisons and more on programs to help reduce the cycle of crime.

The ballot measure led to the lowest arrest rate in state history in 2015 as experts said police frequently ignored crimes that brought minimal punishment.

Jail bookings in 12 sample counties dropped about 8 percent, driven by a reduction in bookings for Proposition 47 crimes, while cite and releases increased, researchers found.

Offenders convicted of those crimes were about 3 percent less likely to be convicted of a new crime within two years, but the researchers said it's not clear if that was because they didn't commit new crimes or because they were less likely to be arrested and prosecuted because of the lower penalties.

Reduced penalties mean fewer drug addicts now seem to be getting treatment, then "are stealing to support their habit," said San Luis Obispo County Chief Probation Officer Jim Salio, president of Chief Probation Officers of California.

Morgan Hill Police Chief David Swing, president of the California Police Chiefs Association, said researchers' findings "are consistent with what police chiefs across the state have seen since 2014" and show the need for a proposed initiative intended for the November ballot that would partly roll back the 2014 law.

It would allow prison sentences for serial thieves, reinstate DNA collections from those convicted of the crimes where penalties were reduced, and bar the earlier release of criminals convicted of additional violent, serious and sexual crimes.

This story includes Associated Press reporting.