The census found just over one in five vacant dwellings were holiday homes, with the remaining 230,000 listed as empty houses, flats and apartments. The lowest vacancy rate was in south Dublin.

Almost 475,000 households were renting – up from 300,000 in 2006 – with the
biggest rise in Laois (up 88pc) and Fingal (up 81pc).

The head count also found there were 29,573 members of the Travelling
community in Ireland – a 32pc rise over five years.

Only 12pc lived in a caravan or mobile home, with almost eight out of 10 in
permanent homes.

Irish Travellers were much younger than the general population, with three out
of four aged 34 or under and almost a quarter between 15 and 24 years
married.

When it comes to religion, Ireland remains a predominantly Catholic country
with more than 84pc of respondents declaring they were Catholic.

There was a 45pc increase in those who had no religion, almost 270,000 people,
while there was a 50pc increase in the number of Muslims, with 49,200 people
making it the most important non-Christian religion.

Pro-marriage, pro-religion think tank the Iona Institute said figures revealed
marital breakdown in Ireland has shown a sixfold increase since 1986.

Professor Patricia Casey said: “Marital breakdown in Ireland is still quite
low by international standards, but the very significant increase in the
number of Irish people who have experienced the tragedy of marital breakdown
is still very worrying and must be addressed.

“The new census figures show that we simply cannot take the institution of
marriage for granted, but we have to work as a society to strengthen it and
promote it.”

Kieran Rose, of the Gay and Lesbian Equality Network (GLEN), commended
same-sex couples for their honesty.

“It is great to see the increasing confidence of lesbian and gay people
leading to greater numbers recording their relationships in the Census, even
though these figures are likely to be an undercount,” he said.

“The 93pc increase in Census 2011 to 4,042 cohabiting same-sex couples,
mirrors the scale of increases across previous censuses.

“One hundred and fifty same-sex cohabiting couples were counted in the 1996
census; 1,300 couples in the 2002 census and 2,090 couples in the 2006
census.

“Since civil partnership became available in 2011, 536 couples, across all
counties in Ireland, entered a civil partnership in the nine months to the
end of December 2011.”