Household overcrowding is an alternative measure of dwelling space that takes into account household composition. Dwelling space is an important dimension of housing quality. This indicator adopts the European Union agreed definition of overcrowding, which takes into account different needs for living space according to the age and gender composition of the household. A household is considered as living in overcrowded conditions if less than one room is available in each household: for each couple in the household; for each single person aged 18 or more; for each pair of people of the same gender between 12 and 17; for each single person between 12 and 17 not included in the previous category; and for each pair of children under age 12. Rooms refer to bedrooms, living and dining rooms and, in non-European countries, also kitchens. This indicator is calculated based on household surveys and measured as a percentage of all survey responses.