Ireland is not producing enough children to maintain the population as it currently stands, the Central Statistics Office (CSO) says.
Women aged 15-49 are having an average of 1.8 children each, which is the second-highest birth rate in Europe after France, but 2.1 is considered the level at which the population would replace itself in the longer term.
However, the figure does not take into account the numbers of people arriving into Ireland, which would increase population numbers.
But the Vital Statistics Yearly Summary Report shows that the number of babies born continues to fall, down to 62,053 in 2017, a drop of 1,844 year-on-year.
The annual birth rate stands at 12.9 per 1,000 of population, compared with 16.1 per 1,000 in 2007.
The report also shows that just over one in three babies was born outside of marriage, with the average age of first-time mothers continuing to rise, up to 31 years, which is an increase of 0.1 years compared with 2016.
For all mothers, the average age is 32.8 years, compared with 31.1 years in 2007.
More than one-third of babies (23,340 or 37.6pc) were born outside of marriage/civil partnerships, and of these 58.9pc were to co-habiting parents.
The highest percentage of births outside marriage or civil partnerships was in Limerick city at 57pc, and the lowest was in Dún Laoghaire-Rathdown at 25.4pc.
A total of 1,041 teenagers had babies in 2017, of which 19 were 16 years or younger. Conversely, 309 mothers were aged 45 or older.
The highest number of births registered was in Dublin city with 7,045, some 11.4pc of all live births in the country, followed by Cork County with 5,472. Just 408 babies were registered in Co Leitrim.
The vast bulk of children (77.3pc) were born to mothers of Irish nationality.
The report also notes that some 30,484 deaths were registered in 2017, of which 15,497 were male and 14,987 female, which is a death rate of 6.4 per 1,000 population. The numbers who died in 2017 were 8.7pc above 2007 figures.
Of these, there were 174 infant deaths registered in 2017, giving an infant mortality rate of 2.8 deaths per 1,000 live births. This compares with 3.1 in 2007.
The neonatal birth rate - the death of infants under four weeks old - was 2.2 deaths per 1,000 live births.
Cancers and heart disease account for just over 60pc of deaths, and more than four-fifths of all deaths were among people aged 65 years and older.
Separately, there were 22,021 marriages registered in 2017, of which 759 were same-sex marriages.
Overall the marriage rate in 2017 was 4.6 per 1,000 of population, 0.2 less than in 2016.
The most recent divorce data, which dates from 2015, shows that the number of couples separating is increasing. In 2015, some 3,289 divorces were granted by the Circuit Court and High Court, an increase of 660 on the 2014 figure.