"Padraig, the Ireland of Mary and Tom is gone".

So a seasoned census enumerator told Padraig Dalton, director general of the Central Statistics Office, as he described the difficulty of gathering data in Ireland this year compared with years gone by.

No more invites in, cups of tea or helpful tips about the potential whereabouts of the neighbours.

In Dalton’s presentation at the MacGill Summer School, on Ireland’s demographics as revealed in Census 2016, the key word was change. The rural-urban divide is growing rapidly. The number of vacant houses in the west is soaring. The fastest population growth is taking place in large sized towns, not cities.

But in some ways Irish people have not changed, according to UCD's Tony Fahey, who presented statistics on family demographics.

A count of how many siblings a child has, instead of how many children the average woman has (about two), shows that those of us who choose to have families still prefer a large brood.

Dip

The average number of children per family in Ireland today is three, while over 30 per cent of children have three or more siblings, according to Fahey’s figures. The Ireland of Mary and Tom, Tom Junior, Áine, Maire and Martin is still here.

This preference for large families has survived through good times and bad. When we had had our last big birth rate downswing in the 1980s, birth rates fell from 74,000 to below 50,000. It’s a significant dip, but significantly smaller than revealed by statistics in comparable countries, says Fahey, and a trend that recovered more quickly.

It’s a trend to be welcomed, he says, with our economy hinging on the availability of a large, young, well-educated workforce.

On a day when our chronic lack of affordable housing was the focus in Leinster House as well as at MacGill, these statistics caught the eye. They suggest a famous feature of Ireland's relationship with property - our love of owning a three or four bed semi-d or bungalow - may stem from our need for an unusually high number of rooms to put the kids in.

Would growing families be happy with a 70m/sq apartment and a balcony instead of a garden, like the homes of our urban continental cousins? Average family sizes here are the highest in Europe, and Fahey says dwelling sizes in other countries may constrain their population growth.

Unattainable

But how well do our changing circumstances allow for this characteristic to persist? The reality is that home ownership will remain unattainable for 30 per cent of current renters, according to Lorcan Sirr, a lecturer in housing at DIT. In order for that cohort to start families of any size, a strategy for long term security in their homes is "urgently needed", he says

Speaking on the Irish Times Inside Politics podcast, Sirr pointed to his experience of Spain, where 85 m/sq apartments with long-term tenancies are sufficient for all stages of life.

Large for a single occupant or couple, you can fit a small family in there when the time comes. And the elderly, perhaps often thought of as needing little room, have space for a lifetime’s accumulation of possessions, and to welcome visits from the grandkids.

But the key difference is security. Who would want to begin growing a large family with no guarantee of where they'll be living in 10 years? Minister Simon Coveney has said he wants to improve tenants rights, but his housing plan makes no provision for it.

At MacGill there is much talk of long-term thinking about Ireland’s future. With housing a problem that is not going away soon, the data provided by the CSO and trends identified by academics like Fahey and Sirr suggest we need bigger changes in order to stay fundamentally the same.

* Sirr, Fahey and Colm McCarthy spoke about housing on the Inside Politics podcast today, which you can find embedded in this article.