Over the last 30 years, household size has declined from an average of 2.91 persons in 1971 to 2.48 in 1991. It continued to decline, though at a slower rate, throughout the nineties, to 2.33 in 2001, representing no statistically significant change since 2000.

There have also been marked changes in household composition, with increases in the proportion of one-person households, and of households headed by a lone parent. Between 1971 and 2001, the proportion of one-person households overall has almost doubled, from 17% to 31%, and the proportion consisting of one person aged 16-59 has tripled, from 5% to 15%. The proportion of people aged 65 and over living alone has remained stable since the mid 80s but, among those aged 25 to 44, the proportion increased from 5% in 1985 to 12% in 2001.

The proportion of households containing a married or cohabiting couple with dependent children declined from 31% of all households in 1979 to 25% in 1991 and then decreased more gradually to 22% in 2001. Households with dependent children headed by a lone parent showed the reverse trend, rising from 4% of all households in 1979, to 7% in 1993 and remaining at this level thereafter.