Three-quarters keep the faith but it will be cold comfort to the Church
In the wake of the revelations around the Tuam Mother and Baby home and the spate of other Church scandals, there may be some relief within the Catholic hierarchy that as many as 78.3pc have kept the faith.
Compared to some of our European neighbours, this would be considered a good result.
But although Catholicism remains the dominant religion of people living in Ireland, the bishops in Maynooth will find cold comfort in these figures. Looked at dispassionately, what is glaring is the substantial drop in the cohort of Catholic faithful, which is ageing. The census figures confirm the anecdotal evidence from parishes across the country.
They also know that a chasm can exist between many of those identifying as Catholic by ticking the box on the census form and those who turn up in the pews on a Sunday.
Groups such as Atheist Ireland may feel, with some justice, that the census figures misrepresent the true number of practising Catholics in Ireland, which is believed to be around 35pc nationally, while in Dublin it may be as low as 18pc, according to surveys carried out by groups such as the Association of Catholic Priests.
The high figures for Catholics among those aged between 0-19 years is likely to be down to parents with children of school-going age, who may not practice themselves, but who have ticked the Catholic box for their children's sake.
The substantial drop in the number of Catholics by 105,800 is undoubtedly linked to the increased secularisation of Irish society and the declining influence of Catholicism, weakened by its own failings. Non-Irish Catholics, such as Poles or Brazilians, who have made their home in Ireland, would be less likely to be swayed by the Irish scandals. The drop among this group was just 26,500.
Another factor in the drop is the natural fall-off among an older and ageing profile of adherents. When the Catholic Church worries about the lack of young people, it has reason to.
The census figures show that 45pc of those with no religion fall into the 20-39 age bracket.
This contrasts with the strong level of faith adherence in the over-65s.
It also suggests that the next census will have more bad news for the mainstream churches.
A more culturally diverse populace is likely to see those defining themselves as having no religion - as well as Muslims, Hindus and Orthodox - continue to increase.