Published Tuesday, 11 December 2012
Last year's census marked the first time people were asked about their national identity.
Participants could select more than one nationality. The NI Statistics and Research Agency shows 29% of people chose Northern Irish.
Almost half of people in Northern Ireland (48%) described themselves as British, while 28% said they were Irish.
The figures published on Tuesday also show 45% of people say they are Catholic - a slight rise since the 2001 census.
The proportion of people who say they are or were brought up Protestant has fallen by 5% to 48%.
Just over 5% of people in Northern Ireland said they do not belong to any religion.
The figures also show the region's elderly population is rising, with 15% of people over 65, while the number of young people (under 16) fell to about one fifth.
And although one in five of the population are living with a long-term health problem or disability that limits their daily activities, 80% said they have a good level of health.
Close to one third of people over 16 have no qualifications, but 24% in the same age range have at least a degree, the statistics reveal.
Also in the 2011 census are details on the number of minority ethnic groups in the region, which have doubled in the past ten years, rising from 0.8% to 1.8%.
The Dungannnon district had the highest rate of population growth, standing at more than one fifth compared to 7.5% average across NI.
DUP deputy leader Nigel Dodds said the census was about "much more than a sectarian headcount or even national identity."
"The lazy assumption that demographics equates to either national identity or political choice should now be laid to rest forever."
The north Belfast MP added: "The overall picture in terms of national identity is one where a clear majority of people are content with the constitutional status of Northern Ireland at present."
He continued by saying those considering themselves Northern Irish come from all sections of the community, before adding that it "underscores the point highlighted by the First Minister that a significant section of our population should not be written off as being off-limits for unionism."
Sinn Féin MP Conor Murphy said that a border poll would provide "a definitive result."
"It's very clear that there has been significant changes since the 2001 census both regarding identity and religious persuasion.
"There will be claims and counter-claims of what this represents when it comes to the constitutional position of the North and what the population are for or against."
The Newry and Armagh MP continued: "Nationalists and Republicans are confident about building a new future based on equality and we see a united Ireland as the best way of ensuring equality for all.
"We are confident in the rationale behind our arguments and of the absolute logic of Irish reunification. If Unionists are confident in their own arguments for retaining the union then they will have nothing to fear with a border poll."
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