Average household size is calculated in two stages:

• The proportion of the population living in communal establishments is used to remove the people living in communal establishments (i.e. not living in households) from the mid-year population estimate to give the number of people living in households for each year.
• The estimated number of people living in households is divided by the mid-year household estimate to give the average household size.

The communal establishment rates for 2001 and 2011 are derived from census data for those years. The rates for other years are calculated using both the 2001 and 2011 Census rates.

1. Average household sizes are rounded to two decimal places.
2. Average household sizes will differ from estimates published in the 2001 and 2011 Censuses, as the rates are calculated based on mid-year estimates at June of each year, not at census day.
3. The mid-year population estimates were rebased in 2013 to take account of the 2011 Census. These revisions have had a small impact on the calculation of average household size.
4. The figures for 2001 to 2011 have been revised since the publication of ‘Estimates of Households and Dwellings, 2012’ to fully reflect the results of the 2011 Census.