The population of the 26 Counties in April 2004 is at its highest figure since 1871 amid an Irish baby boom.
According to population estimates figures released today by the Central Statistics Office in Dublin, the population increased by 64,900 or 1.6 per cent compared with the previous April.
This puts the population at 4.04 million and compares with the census return for 1871, when the population in the same 26 Counties reached 4.05 million.
Irish emigration is at its lowest level, at 18,500 for the year, since the Central Statistics Office began collecting data on migration in 1987.
Net immigration contributed 31,600 to the annual increase. But the main feature of the 2004 figures was a widening gap between the number of births and deaths - which has grown from 17,500 in the 12-month period ending April 1995 to 33,300 in the corresponding period to April 2004.
The age profile of emigrants was younger than that for immigrants. Some 54 per cent of emigrants were aged 15-24 years, while half of all immigrants were aged 25-44 years.
Nearly a third of immigrants are returning Irish nationals.