For anoraks and non-anoraks alike, the Central Statistics Office's (CSO) 2006 Statistical Yearbook is a fascinating compendium of facts and figures. It does not tell us anything new or startling, but the Yearbook does arrange what we know about the past and present in a fascinating way.

In just four short years between 2002 and 2006, the Republic's population has grown from 3,917,303 to 4,234,925. The phenomenal increase corresponds to the 400,000 people which the CSO estimates are non-Irish nationals living here.

As the table shows, estimated net annual immigration has gone from a trickle to a flood in just four years; from 2,000 each year between 1996 and 2002 to 46,000 each year between 2002 to 2006.

This immigration of mainly male workers from eastern Europe isn't just affecting the population. As the yearbook shows, it also affects the gender balance in the population.

In the age cohorts most represented by recent immigrants from accession states - between 20 and 39 - males outnumber females. By contrast, all the Irish men who emigrated in the 1980s and early 1990s have taken their toll on the 39 to 49 age cohort, where females still outnumber males.

And the share of women at work continues to rise, increasing from 41.7 per cent in 2002 to 42.5 per cent in 2006. Looking at the overall picture from another statistical angle - the share of women who work as distinct from the number of workers who are women - we can see that, despite an influx of largely male migrant workers during the period, the share of women who work has risen from 48.8 per cent in 2002 to 51.4 per cent in 2006.

One trend is more worrying: From a level of 77,000 in 2002, the number of unemployed has risen to 85,600 in 2006. The increase is a modest one but takes place against the backdrop of a booming economy. For that reason it begs the question: what might happen if the boom stops?

So far it has not and if unemployment has risen a little, employment growth has kept pace with it: Ireland's unemployment rate, 4.2 per cent, remains where it was in 2002.

Data on poverty is given only for the years 2003 and 2004. It shows a decline in poverty that, while modest in percentage terms, still represents a significant change for a single year.

The share of persons in "consistent poverty" - i.e. enjoying less than 60 per cent of the average national income - fell from 11.5 per cent in 2003 to 10 per cent a year later.

One of the largest chapters of the publication, chapter seven, is devoted to the economy. Economists usually focus on the rate of economic growth for a particular year. Much more striking is the comparison between the level of economic activity in 2005 - the latest year for which we have full year figures - and that only three years previously. Between 2002 and 2005 the monetary value of annual economic activity rose from €106.2 billion to €135.9 billion, or by a staggering 28 per cent.

But this monetary value is measured in what economists call "current market prices"; some of it reflects not added activity per se, but higher prices. Between 2002 and 2006 the Republic's average price level, as measured by the Consumer Price Index, increased by 8 per cent.

In a way this brings us back to where we started: the increase in the population over the period was also 8 per cent.

An interesting coincidence perhaps, but also a reminder that without good planning and infrastructure, a rapidly growing population in the State will lead to rising prices and growing congestion.