Almost one third of people sent to prison in 2007 were not born in Ireland.

According to the latest report from the Irish Prison Service, more than 11,000 were convicted of an offence last year.

On average there are 3,321 offenders behind bars on any given day, an increase of 4.1%.

There has also been a rise in the number of those jailed for drug offences, with 529 sentenced in 2007.

While sentences for road traffic offences increased also; the 1,565 sent to prison on these charges represented a 7.8% increase.

It costs on average €97,700 a year to keep a prisoner in jail.