Limerick City has the highest number of births outside marriage, according to the latest figures published by the Central Statistics Office.
Overall figures for the second quarter of this year show 4,689 births outside marriage, accounting for 30 per cent of all births, an increase of almost 10 per cent over 1994 figures.
While 47.2 per cent of births in Limerick City were outside marriage, Roscommon had the lowest rate at just 15 per cent.
In general, the rates were higher in urban areas, although Dún Laoghaire-Rathdown bucked this trend with a rate of 21.3 per cent.
While the overall figures are slightly down on last year, sociologists say the increasing trend of births outside marriage in recent years in Ireland follows trends in marriage and birth rates throughout Europe.
Two of the main factors contributing to the rise in births outside marriage, they say, are socio-economic factors and an increase in cohabiting couples.
Cherish, a support group for single parents, says more women are choosing to reject marriage because the stigma of having a child outside marriage has been reduced. It also says many parents are now more cautious about getting marriage.
The statistics show a slight increase in the birth rate, with 15,582 births, a rise of 0.3 per cent on the same period last year.
The figures reflect the trend toward smaller family sizes. Only 28 per cent of mothers had two or more children, compared with a figure of 35 per cent in 1994.
Limerick also had the youngest average age for mothers, 26.4 years, compared to the national average of 28 years.
Dún Laoghaire-Rathdown had the oldest average age for mothers at 30.3 years.
The number of marriages remained broadly similar to last year.
Statistics also reflect a slight decrease in the death rate, with 7,203 deaths registered in the second quarter of this year, 433 less than last year.
Overall, the number of deaths is 8 per cent less than figures for 1994.
