According to a new report from Helsinki University the number of custodial prison sentences handed down by Finnish courts decreased by 42 percent between the years o f 2004 to 2016.
Criminology researcher Hannu Niemi said the decline was mainly correlated to a decrease in crime, which was in turn caused by Finland's changing age demographics.
"It is most often young adults who commit crimes, so an aging population led to a decrease in criminality," Niemi said.
The study found that the majority of crimes carried out in Finland are not severe generally; and the decrease in crime was most noticeable in mandatory prison sentences of less than two years.
Life sentences double
While the statistics for minor crimes have declined, the number of people serving longer-term sentences for more serious crimes has gone up considerably.
Niemi said that the number of convicts serving life sentences (which in Finland range between 10-15 years generally) has doubled since 2004.
One of the reasons for the increase in long-term sentences among prisoners is that the average duration of life-term sentences has risen since the 1990s. In the 90s life sentence amounted to just over 10 years, and has increased to 14-and-a-half years.
At the beginning of 2016 there were about 200 people serving life sentences in Finland, Niemi said. Some 2,500 people were incarcerated in Finnish prisons in 2016.