The number of people sent to prison in the Republic in 2004 was 10 per cent lower that in 2003.
However, because this was a reflection of the fall in the number of people detained under immigration law - who tend to spend short periods in custody - demand for prison places rose by one per cent in the same period.
The Irish Prison Service (IPS) annual report for 2004 shows that the average cost of keeping an offender in custody in that year was €83,800, down by €4,150 on the equivalent figure for 2003.
The director general of the IPS, Brian Purcell, said the reduced cost was the result of specific measures taken that year, including the adoption of a strict overtime budget and the closure of the Curragh and Fort Mitchel prisons.
A total of 8,820 people were sent to prison last year, compared to 9,814 in 2003, a reduction of 10 per cent. The daily average number of people in custody in 2004 was 3,199, an increase of 1 per cent on the previous year.
Of those committed to prison, 17.6 per cent (1,874) were foreign nationals, 946 of whom were held under immigration laws.
Examining committals by age group, the report recorded that, as in previous years, young adults were the most likely to be in prison. Those aged between 21 and 40 years accounted for the majority (65 per cent) of committals under sentence in 2004. Of these, 3,009 were men.
There was also a significant increase - from 746 to 970 - in the number of committals relating to Group 1 offences (Offences against the person).
Meanwhile, the number of asylum applications received by the Department of Justice in 2004 fell by 40 per cent on the previous year, according to the department's annual report.
