Irish families are now among the smallest in Europe, with fertility rates dropping to the lowest level recorded.
The average Irish family now has just 1.6 children, according to the 2002 census, down from 1.8 in 1996 and 2 in 1991.
The fastest growing units consists of families (whether married or not) without children. Meanwhile, the number of families with four children or more has halved over the past 20 years.
There has also been a big increase in the number of cohabiting couples, up from 31,300 to 77,600. Almost two-thirds of these were childless couples.
Cohabiting couples accounted for 8.4 per cent of all family units in 2002, compared to less than 4 per cent in 1996. Some 52,000 children live with cohabiting couples.
The census also records a significant increase in the number of same-sex cohabiting couples, from around 150 in 1996 to almost 1,300 in the current census. Two-thirds of these were male couples.
There were almost 153,900 lone-parent families in 2002, and 85 per cent of these were headed by females. In almost 40 per cent of such families, a widowed person was the parent.
Overall, the population increased by 291,000, or 8 per cent, between 1996 and 2002.
There were 1,287,958 private households in total in 2002; some 8,341 were temporary. The average size of households continues its long-term decline, from 3.14 in 1996 to 2.94 last year.
The number of childless-couple households was up almost 40 per cent in six years.
In line with the trend towards an older population, over 113,000 pensioners are now living alone and 60,000 of these are 75 or more.
Among those enumerated in the census were 37,000 people in hotels and guesthouses, 7,000 in hostels and 56 people on campsites. Some 23,000 hospital patients, 3,000 prisoners, 7,000 in religious communities and 17,000 in nursing homes also filled out the questionnaire.
