The Family:Cohabiting couples are one of the fastest growing family units in the State, new census figures show.
The number of unmarried couples living together has increased by more than 50 per cent in four years, rising from 77,600 couples in 2002 to 121,800 last year.
Cohabiting couples now account for 11.6 per cent of all family units.
The growth in this form of family unit comes at a time when the Government is examining ways of providing fairer treatment for unmarried couples in areas such as tax, inheritance rights and social welfare.
The number of same-sex couples recorded in the 2006 census, meanwhile, was 2,090, an increase from 1,300 in 2002. Two-thirds of these were male couples.
Women, meanwhile, are continuing to have significantly fewer children compared to previous years. Within a generation, the average number of children per woman has declined from 3.5 to 2.2.
Falling fertility is also having an effect on family sizes, which have decreased from an average of 2.2 children per family in 1986 to 1.4 in 2006.
As with the majority of western countries, the population in Ireland is growing older, although it is still significantly younger than in most EU countries.
The average age of the population has increased by six months since the last census, rising from 35.1 years in 2002 to 35.6 in 2006.
The Fingal area of north Dublin had the youngest population (an average age of 32.2 years), followed by Kildare (32.8 years). Roscommon had the oldest population (average age 38.3 years), followed by Leitrim (38.1 years).
While the population is ageing, Ireland does not have an age dependency problem yet, with substantially more young people under-14 (864,000) compared to people aged 65 plus (468,000).
The number of people of working age in the economy has grown from 1.6 million in 1961 to 2.9 million in 2006, which has ensured that age dependency ratios have declined over this period.
The size of households, meanwhile, continues its long-term decline. The average size of a private household fell from 2.9 in 2002 to 2.8 in 2006.
The most common form of household was a couple with children (35 per cent). One-person households and couples without children accounted for a further 40 per cent, followed by lone parents and their children (10 per cent).
However, lone parent families increased by some 23 per cent to almost 190,000.
Central Statistics Office officials said the rise may be due to more precise data provided under a revised questionnaire.
The number of people who were divorced has increased significantly, with 59,500 people recorded as divorced, a 70 per cent increase over the 2002 census when the same figure was 35,000. When the number of separations are included, the overall rate of marital breakdown - the proportion of ever-married adults who were divorced or separated - has risen from 7.5 per cent in 2002 to 8.7 per cent last year. Limerick city had the highest rate of marital breakdown (12.9 per cent), followed by Dublin city (11.6 per cent). Galway county (6.3 per cent) and Cavan (6.4 per cent) had the lowest rates.
