The Republic's population grew faster in 2001 than in any other EU state, according to figures published yesterday. The population grew by 58,100 to 3.884 million people, an addition of 15 people for every 1,000 inhabitants since the previous year.
But Ireland was an exception to the EU rule. The figures from the statistical office, Eurostat, will do nothing to allay fears that several of Ireland's European neighbours are heading towards a pensions and welfare crisis, with a smaller proportion of workers unable to support increasingly ageing populations.
Ireland's rate of population growth is almost four times the average figure for the EU of four people for every 1,000 inhabitants. In Germany and Austria, the increase was only two people per 1,000.
Dr Tony Fahey, a demographer at the Economic and Social Research Institute, said the figures confirmed the European Union's pattern of weak demographic performance, which contrasted sharply with the US and Australasia. "Ireland has bucked the trend by staying at the upper end of the range for population growth and fertility rates," he said.
For the EU as a whole about three-quarters of the total population increase was due to immigration, and only a quarter to natural increase.
In Ireland, more than half of the increase in population is attributed to migration: in 2001, the number of immigrants exceeded the number of emigrants by 30,000. But the natural increase in population - the difference between the number of births and the number of deaths - was not far short of the effect of migration at 28,000.
The rate of natural growth, 7.3 people per 1,000 inhabitants in Ireland, was far higher than anywhere else in Europe. The next highest was France with 4.2 people per 1,000, the Netherlands and Luxembourg with 3.9 and Spain with 1.4.
Italy's natural increase was only 0.1 people per 1,000 while in Germany it was -1.1, Sweden -0.3 and Greece -0.1, where deaths exceeded births.
In these three countries the populations only increased because of migration. Part of the explanation for the rate of natural growth in Ireland is that the rate of mortality has dipped.
The number of deaths per 1,000 inhabitants in 2001 was 7.7, compared to 8.2 in 2000. At the same time, the birth rate has increased: the birth rate in Ireland was 15 children per 1,000 population, up from 14.3 in 2000.
Dr Fahey said that the lower death rate was attributable to a young population.
Ireland was also benefiting from the peak birth rate in 1980 - the babies born then are now entering their child-bearing years.
Ireland was the only EU country to show an increase from the previous year in the fertility rate: the number of children born alive to a woman during her lifetime.
The EU average fertility rate for 2001 was 1.47 children per woman, compared with 1.48 in the previous year.
In Ireland, the rate rose from 1.89 children per woman to 1.98, which Eurostat described as a sharp increase. The fertility rate in the UK was 1.63 children per woman, in Germany 1.29, in France 1.9, in Italy 1.24 and in Spain 1.25.
Dr Fahey said the puzzle in Ireland was why fertility had not fallen to the low levels seen in other strongly Catholic countries such as Italy and Spain, which have the lowest fertility rates in Europe.
"It did fall sharply in the 1980s but has bottomed out at quite a high level," he said.
But Ireland's fertility rate is still below the rate of 2.0 needed for a couple to replace itself and below the United States's fertility rate of 2.06 and India's 3.04.
Although Ireland's birth and fertility rates are high relative to the rest of Europe, they are still low compared to the past.
In 1980, the birth rate was 21.8 births per 1,000 and the fertility rate stood at 3.3 children per woman. In 1980, births outside marriage were 5 per cent of the total in Ireland.
In 2001, the proportion was 31.2 per cent, slightly down on the previous year's 31.8 per cent. That figure is higher than in the Netherlands (22.6 per cent) and Germany (23.6 per cent) but still lower than in the UK (40.1 per cent), Denmark (44.6 per cent) and Sweden (55.5 per cent).