Last week's release by the CSO of the census volume on Birthplaces, Nationalities and Migration has revealed that the scale of migration to and from Ireland in recent years has been much larger than had been suspected, writes Garret FitzGerald
Earlier official estimates of immigration to Ireland between 1996 and 2002 had suggested an influx of some 270,000 people, about 125,000 of these being Irish people returning after a period abroad, and 145,000 being non-nationals.
But these figures now seem to have represented a significant underestimate.
This has emerged from the 2002 population census which has shown that, in the 12 months ended April 2002, the number of people usually resident here who had been living elsewhere a year earlier was 60 per cent higher than the figure of 47,500 immigrants that earlier had been estimated by the CSO for this period.
We can now see that during that 12-month period three-quarters more Irish nationals than had previously been thought had returned to live here, and that the number of non-nationals coming to live here during these 12 months was also 50 per cent greater than had earlier been estimated.
Unfortunately we don't know when or how during this 1996-2002 period this underestimation factor began to arise. But, even if it arose only in the late 1990s, the scale of return by Irish-born people must have been at least 50,000 higher than had been earlier estimated, and immigration by non-nationals was probably some 70,000 higher.
Thus the total inflow of new Irish residents during these six years appears to have been closer to 400,000 than to the earlier estimate of 270,000.
Given that the census also showed that in 2002 the total population was only 20,000 higher than had been estimated, this implies, that the flow of short-term Irish emigration during this six-year period may also have been a good deal greater than had been suggested by the earlier CSO annual estimates of migration.
Of course, not all of these 200,000-225,000 non-national immigrants between 1996 and 2002 remained in Ireland for more than a year or two.
For we know that the number of people born abroad who were resident here last year was only 137,000 greater than in 1996, and some 20,000 of these were probably Irish nationals born abroad.
This means that about half of the estimated 200,000-225,000 non-nationals who stayed here for at least a year between 1996 and 2002 must have already left when last year's census was taken. It is particularly interesting to see the net impact that all this has had on the age pattern of the population in recent years.
The figures show that the small outflow of Irish-born children under 10 in 1996 who emigrated with their parents during the following six years were replaced by three to four times as many foreign-born children of that age coming to Ireland with immigrating parents.
Of course, some of these latter were children of Irish parents returning here after gaining experience abroad.
Of the next age cohort - the group born here between 1971 and 1986, who were aged 10 to 24 in 1996 - some 8 per cent had left the country by 2002.
But by that year four-fifths of this loss had been replaced by children and young people born elsewhere; some of the younger among this age cohort being foreign-born children of earlier Irish emigrants returning here with their parents, but most being young foreigners coming to work, or in some cases to study, in Ireland.
The next-oldest age cohort - those born between 1956 and 1971, who were aged 25 to 39 in 1996 - had its numbers strongly reinforced between 1996 and 2002 both by a substantial inflow of foreign-born immigrants, and also by a slightly smaller number of returning Irish emigrants.
The number of older emigrants, aged 31 or over in 2002, who returned during this six-year period almost equalled the contemporaneous outflow of younger Irish emigrants, which means that for the first time in centuries there was almost no net emigration of Irish people.
A consequence of the large scale of foreign-born immigration during this period has been a significant rejuvenation of the population.
By 2002 the surviving native population under the age of 47 had been boosted by more than one-eighth through the presence here of almost 280,000 foreign-born people, almost half of whom had come to live here within the immediately preceding six years.
This rejuvenation of the population will help to produce resources needed to pay the present and future pensions of the older generation in the decades ahead; although the persistent failure of the Government to allow the asylum-seeker proportion of these younger immigrants to work is depriving us of some of the benefits of this inflow.
Equally negative, and quite inexplicable, is the Government's persistent refusal to permit the spouses of Filipino nurses to work here, a refusal that is currently helping to cripple further the health service, as many of these nurses move off with their spouses to other more hospitable European countries.
I should perhaps add that there is always a possibility that census figures underestimate the population, and some non-nationals registered here may have been reluctant to record their presence on a census.
The scale of such understatement is unlikely to be very large, however. Thus 5,600 Chinese were recorded in the census as usually resident here on census day, to which should be added some 600 others visiting the country.
This compares with 12,000 Chinese registered with Garda authorities at some point during the year, some of whom were students staying for six months or less.
Even allowing for some illegal immigrants, these figures suggest that figures of 50,000 or 65,000 Chinese in Ireland recently published by elements of the media are fictitious.