A comparison of the results of the 2011 censuses in the Republic and Northern Ireland shows clear differences between life in the two near neighbours.

The report by the Central Statistics Office (CSO) and the Northern Ireland Statistics and Research Agency (NISRA), published today, highlights clear gaps between the two jurisdictions when it comes to age, gender, marital status, population density and household size.

The population of the island was 6.4 million at the time of the two censuses, carried out within weeks of each other in 2011, with the Republic accounting for 72 per cent (4.6 million) of the total and Northern Ireland 28 per cent (1.8 million).

The report points out that, since 2002, the population in the Republic increased at about two and a half times the rate of Northern Ireland, at 17 per cent and 6.9 per cent respectively.

Across the island, the highest rates of population growth were seen in Fingal (79 per cent), Meath (75 per cent) and Kildare (71 per cent) over the last 20 years with Belfast (-4.1 per cent) and Cork city (-6.3 per cent) the only areas to experience a decline.

The population density for the island as a whole stood at 78 persons per km2, an increase of 25 per cent since 1991. The population density in Northern Ireland stood at 134 persons per km2; exactly double that of the Republic at 67 per km2.

Strong population growth in the Republic saw population density increase by 30 per cent between 1991 and 2011. The Northern Ireland rate went up 13 per cent in that period.

There are more women than men in both jurisdictions (3.24 million to 3.16 million across the island) with Northern Ireland recording 961 men for every 1,000 women and the Republic reporting 981 men for every 1,000 women.

The median age, the point at which half of the population is younger and half is older, was 34 in the Republic, the lowest of any EU member state. The median age in Northern Ireland, while higher at 37, was also comfortably lower than the EU average of 41.

“The highest median age can be seen in eastern areas of Northern Ireland, in particular in Ards, Castlereagh, Larne and North Down at 41. The lowest median age of 31 was found in Galway City,” the report states.

Children aged up to 12 years accounted for 19 per cent of the population of Ireland, compared to 17 per cent in Northern Ireland, which the report says reflected higher birth rates in Ireland in recent years. Over 65s accounted for 15 per cent of Northern Ireland’s population, compared with 12 per cent of that in the Republic.

Single life was a more common occurrence for residents of the Republic (42 per cent) than the North (37 per cent). The North’s older population showed through when it came to the number of widowed people at 6.7 per cent of the population, compared to 5.3 per cent in the Republic.

There was parity in the two jurisdictions when it came to the proportion of people who were married or separated at 51 per cent. Divorce was a more common occurrence in Northern Ireland at 5.4 per cent of the population to the Republic’s 2.4 per cent.

Households in the Republic were larger on average than in the North, at 2.73 and 2.54 persons respectively. The largest average household sizes were concentrated in the Dublin commuter belt and Magherafelt areas respectively.

In Northern Ireland, Catholics had the largest average household size at 2.76 persons, while in the Republic it was those of “Other Religions” at 2.95 persons.

Regarding religion, one in 10 people in Northern Ireland said they had no religion, compared to 5.9 per cent in the Republic. Some 21 per cent of those living in north Co Down said they had no religion, the highest rate on the island, which was almost double the highest rate in the Republic, 11 per cent in Dublin. The midlands and north-west areas reported the fewest people of no religion.

The report states that 202,000 people in Northern Ireland (11 per cent) were born outside the jurisdiction, compared to 17 per cent (766,800 people) in the Republic. One in five of these people in Northern Ireland were born in the Republic, compared to the 8 per cent who were born in the North but live in the Republic.

Non-white ethnic groups accounted for just 1.7 per cent of the total population of Northern Ireland and 5.8 per cent of that of the Republic.

There were 1,300 Irish Travellers in Northern Ireland, accounting for 0.1 per cent of the population, compared with Ireland, where the population of 29,500 made up 0.7 per cent.