A 2014 California voter-approved initiative that reduced penalties for certain drug and property crimes has led to the lowest arrest rate in state history as police frequently ignore those illegal activities, experts say.

Proposition 47 lowered criminal sentences by reducing them from felonies that can bring long prison sentences to misdemeanors that instead bring up to a year in jail.

Recent state Department of Justice statistics show the number of felony arrests plummeted 28.5 percent last year, while misdemeanor arrests rose about 9 percent over 2014. That resulted in 52,000 fewer arrests overall and the lowest arrest rate since record-keeping began in 1960, the Associated Press reports.

It's too soon to say whether the changes are helping spur rising crime rates, though Lofstrom and other researchers are watching the relationship closely.

State Department of Justice figures show violent crime jumped 10 percent last year over 2014. Property crimes also increased, including a nearly 12 percent increase in shoplifting and nearly 11 percent increase in thefts, two crimes affected by Proposition 47.