Migration: Immigration has fallen over the past two years, but still accounts for 45 per cent of population growth, according to the latest population estimates.
The largest single group of immigrants other than returning Irish come from the UK. The UK contributed almost 12 per cent of all immigration to Ireland last year. The next largest group was the Chinese, at nine per cent.
The total number of immigrants into Ireland in the year ending April 2004 was 50,100, compared with a high point of 66,900 in the year ending April 2002.
When those emigrating are deducted from this figure, there was net immigration of 31,600.
Population flows in both directions are down on last year, with only 18,500 people emigrating last year, the lowest since 1987.
Those who did leave the State were young, with 54 per cent of them between the ages of 15 and 24. According to Mr Gerry O'Hanlon, director of the CSO, it is likely that some are young people spending a year or two in countries such as Australia or New Zealand before resuming studies or taking up a career back in Ireland.
In comparison, those immigrating are from a slightly older age group, with half of all immigrants coming from the 25-44 age group.
Immigrants are divided into three roughly equal groups: returning Irish people, who account for 34 per cent; nationals of the pre-enlargement EU, including the UK, and of the USA, who account for about 36 per cent; and nationals of other countries, including those now part of the enlarged EU, who account for 30 per cent.
Eight per cent of immigrants in 2004 came from central and eastern European countries.
The figures also show a significant decrease in the number of Irish returning from abroad, compared with the dramatic numbers who returned from the end of the 1990s. In 2002 the number was 27,000, and the figure averaged out at about 25,000 over the previous three years, with over 100,000 returning in four years.
However, those returning were down to 16,900 in the year ending in April 2004, a similar figure to the 17,500 who returned in 2003.
As well as using the quarterly National Household Survey, the CSO draws from data compiled at airports and seaports, the Register of Electors, the Child Benefit Scheme, and the numbers of visas, work permits and asylum applications in drawing up population estimates and migration flows.