Almost one third of all births in Ireland were outside marriage last year, new figures from Central Statistics Office (CSO) show.
The proportion of births outside marriage has increased from just under 25 per cent to 32 per cent over the last decade.
The figures - contained in the vital statistics on births, deaths and marriages for 2005 - show the highest percentage of births outside marriage last year was in Limerick City (59.9 per cent), while the lowest was in Leitrim (17.1 per cent).
The youngest average age for giving birth was also in Limerick (25.9 years) while the oldest was in Dún Laoghaire-Rathdown (30.0 years) and Leitrim (30.0 years).
There were 11 births among teenage women aged 15 or younger in 2005, one of whom had already given birth previously.
Overall, there were a total of 61,042 births registered and 27,441 deaths registered in 2005 - representing a natural population increase of 33,601.
There were 14,232 births registered in last three months of the year, 7,246 males and6,986 females, 14 per cent higher than in 1996 when 12,451 babies were registered.
There were 6,360 deaths registered in the final quarter of 2005 - 3,291 males and 3,069 females - which is 12.2 per cent lower than in 1996 when 7,241 deaths were registered.
The main causes of death were diseases of the circulatory system, namely heart disease and stroke, as well as malignant neoplasms of the larynx and trachea, bronchus and lung.
The number of infant deaths fell significantly last year with 244 deaths, a decrease from 300 in 2004.
