DEMOGRAPHICS ARE changing the face of Northern Ireland with bewildering rapidity and profound implications not just for politics but for the economy and society as a whole.
The balance of power between nationalist and Unionist is fundamentally shifting, with Protestants believing they are steadily declining both in numbers and political power. The corollary is that Catholics believe that nationalism is very much on the move.
Discussions of demographics are highly charged politically. They can quickly deteriorate into overheated and sometimes mischievous speculation that a Catholic majority is imminent and that this will inevitably lead to Irish unity.
Such an outcome is dependent on the arrival of a voting majority, and on the assumption that Catholics would then unanimously vote for a united Ireland. All of this is highly questionable. But what is certain in terms of practical politics is that the power relationships between the two communities are fundamentally changing the fabric of Northern Ireland's politics.
The old ratio of two-thirds Protestant to one-third Catholic, the backdrop to politics for so many decades, has gone. In its place is a very different mathematical and political model, with the census results expected to confirm that rapid movement is continuing.
On the streets, the Protestant perception of losing ground can have violent results. This was vividly seen in the recent rioting in the north Belfast troublespot of Ardoyne, with loyalists seeking to prevent Catholic schoolgirls attending school in a Protestant area.
Local Protestants presented themselves as a dwindling community battling against Catholic "encroachment." They complained of a twofold alienation, claiming Catholics were making ground both politically and geographically at Protestant expense.
Most of the loyalist marching controversies of recent years have resulted from demographic changes, as Protestant organisations sought to continue parading through districts that were once Protestant but which are now Catholic.
In political terms the advances of nationalism are clear enough, embodied as they are in the Good Friday Agreement, which gives Sinn Fein and other nationalists places at the highest level of devolved government.
On the Protestant and Unionist side recent debate has centred on a phrase used by John Reid, the Northern Ireland Secretary, who declared: "Northern Ireland must not become a cold place for Protestants, or we will have failed." Mr Reid noted that Unionist confidence has declined while the Catholic community "breathes confidence, coherence, dynamism and energy". Assertions by a number of Unionist politicians that it has already become a cold place are partly fuelled by the steady growth of the Catholic population.
This perception can only be reinforced by new figures confirming that the Protestant community is steadily losing in the numbers game.
Almost every part of the statistical calculations used to work out population numbers is open to challenge and argument, but some points are clear.
Population changes rest on birth rates, death rates and emigration. Catholics have a distinct majority of school-age children. Each year roughly 5,000 more Protestants than Catholics die, because the Protestant population has an older age profile.
Emigration patterns are almost entirely a mystery, but most of the signs point to a reversal of traditional patterns, which used to see many more Catholics than Protestants emigrating.
There is now a "brain drain" of Protestant teenagers going to universities and colleges in England and especially Scotland. There are suggestions that many of them stay to work in Britain rather than returning home, while more Catholic young people go back to Northern Ireland after college.
One close observer summed up: "Protestants are losing on all the known demographic indicators. …