Ireland has been a “clear outlier” in Europe for having a relatively large average household size, according to new research published by the Economic and Social Research Institute (ESRI).

The country has a higher fertility rate than most EU countries even though it is now well below replacement level. It also has a younger population and higher share of households with children.

The ESRI research compared the trends in household size in the Republic with other European countries for the period 2005-2021.

The average number of people per household in Ireland was 2.74 in the 2022 census. Across Europe the average figure was 2.2 members per household that same year.

“Ireland is a very clear outlier for much of the period with consistently high household size levels; since 2011 onwards Ireland has had the highest level of average household size of all the countries presented,” the report says.

It adds that Ireland is highest alongside Spain, Portugal and Greece.

The Nordic countries of Denmark, Sweden, Finland, Norway and also Germany have the lowest.