Population figures: The population of the 26 counties has reached its highest for 133 years. It now stands at 4.04 million, compared to 4.05 million in 1871, according to the latest figures published by the Central Statistics Office.

The figures issued yesterday are based on the population and migration estimates for April 2004, drawn primarily from the National Household Survey.

The increase is divided roughly equally between natural growth (excess of births over deaths) and immigration.

Some 62,000 babies were born up to April of this year. When the number of deaths is deducted, there was a natural increase in population of 33,300.

Immigration of 31,600 made up the rest, bringing the overall increase in population to 64,900, or an increase of 1.6 per cent on the previous year.

According to the director of the Central Statistics Office, the figures reflect "the growth of the greater Dublin area".

The biggest increase in population was in the mid-eastern area - 2.9 per cent.

This was followed by an increase in the midlands of 2.8 per cent, and 2.1 per cent in the Border region, which includes Co Louth.

The south-eastern region saw an increase of 2 per cent.

The western region had a population increase the same as the national average, at 1.6 per cent.

Both the mid-west and the south-west had smaller increases, at 1 per cent and 1.4 per cent respectively, while the population of Dublin county increased by 1 per cent.

While births are creeping up, they have still not hit the high point of 1980, when 72,000 children were born.

This was also the year of the highest recent natural increase in population.

However, in those years there was also some emigration and negligible immigration, so the overall population did not increase as dramatically.

The 1981 census showed an increase of just over 39,000 on the previous census two years earlier in 1979 (it had been postponed from 1976 for financial reasons), while there has been an increase of almost double that in one year since 2003.

While a full census takes place every five years (with some exceptions for financial or other reasons, like the foot-and-mouth outbreak two years ago), the CSO also carries out surveys like this one to measure population shifts and citizens' living standards and lifestyles.

The next full census is due to take place in 2006.