The downward trend follows a 45 per cent jump in the numbers being sent to jail in the five-year period from 2007 to 2011.
All crime types apart from burglary have declined since 2008, with gun and drug crime down by more than half since 2007-2008.
While the full set of data for incarceration rates last year will not be available until the Irish Prison Service annual report is published in the weeks ahead, informed sources have told The Irish Times that the rates are down.
In 2011 there were 17,318 committals to prisons, but that fell back to about 17,000 in 2012, according to sources.
The prison population on any one day has been about 4,500 in recent years, but last year reduced closer to 4,100 for most of the year.
The lower number of committals and the impact of a new community-return scheme, under which almost 150 non-violent offenders are on release on licence and on condition they do not reoffend, have combined to bring down the daily prison population.
The number of foreign nationals in Irish prisons is also falling, down by 18 per cent in the five-year period to the end of 2011. Fewer foreign people are coming to Ireland for work since the recession started and so fewer are coming to the attention of the Garda.
The reduction in the number of committals generally has also eased the need for prisoners to be granted open-ended so-called “temporary” release to make room for more serious offenders.
In recent years the numbers on temporary release have reached 900 on any one day, but reduced to between 550 and 600 on most days last year, according to sources.
There were 11,934 committals in 2007, increasing 14 per cent the following year and a further 14 per cent in 2009, to 15,425 committals that year.
And while overcrowding had already become very acute because of the increased numbers, the committal rate jumped by 11 per cent in 2010 to 17,179. Rates showed signs of stabilisation in 2011 when the increase in committals was just 0.8 per cent. In 2012 that stabilisation for the first time in six years turned to a decrease.
