Across England and Wales, the number of sentences handed out for thefts rose for the first time since 2011, with concerns raised about the number of investigations being launched and completed into low-level crime.
Ministry of Justice figures show 451 people were sentenced for committing a theft offence in the Devon and Cornwall Police area in 2022 – down from 495 in 2021, and the lowest figure since 2010, when comparable records began.
Nationally, 36,903 sentences for theft – which includes shoplifting, blackmail, burglary and stealing a vehicle or bicycle – were dished out last year, up from 33,912 the year before.
The Police Federation of England and Wales said the increase is "to be expected given the recent pivot towards prioritising theft and burglaries".
But the rise is well below previous years, with the number of sentences steadily declining – a decade ago, there were 126,359, of which 2,309 were in Devon and Cornwall.
The PFEW has called for "significant improvements" to be made to the criminal justice system.
A PFEW spokesperson said: "The Government must properly recognise and support police officers who are exhausted, overworked, underpaid and struggling to deliver the service they want to give because of the increasing demands of the job as part of the solution to improve rates.
"Ultimately, it is easy to take quick wins from individual figures but often this does not tell the whole story and it is imperative that we consider new data in a collective way to be able to draw out the right solutions to improve the criminal justice system as a whole."
Prosecutions and convictions across the country also rose for the first time since 2011 last year, with 42,300 and 36,700 recorded respectively.
The average custody length thieves received in 2022 was 11.2 weeks, down from 12.9 the year before, while the average fine handed down rose slightly from £122 to £124.
Meanwhile, separate Home Office figures show 16,648 theft offences were recorded in Devon and Cornwall last year – down from 18,558 in 2021.
Some 36,501 offences were recorded in 2012, a decade ago.
A Crown Prosecution Service spokesperson said: "Theft can have a serious impact on victims, and we are determined to bring perpetrators to justice whenever our legal test is met.
"We can only prosecute cases that are referred to us following an investigation and will continue to work closely with police to bring offenders to justice."