The 1991 General Household Survey, published yesterday, reveals that the proportion of families headed by a lone parent more than doubled - from 8 per cent in 1971 to 19 per cent in 1991 - and the traditional family declined from 31 per cent in 1979 to 25 per cent.
The proportion of people living alone increased from 9 per cent in 1973 to 14 per cent in 1991.
Average household size fell from 2.91 to 2.48 members between 1971 and 1991. Eight per cent of families with dependent children headed by a married or cohabiting couple contained at least one stepchild in 1991.
The number of women aged 18 to 49 who were married when survey interviews were conducted fell from 74 per cent in 1979 to 61 per cent.
In 1991, 8 per cent of men and 7 per cent of women aged 16 to 59 were cohabiting.
The proportion of people aged 75 and above increased from 4 per cent in 1971 to 7 per cent in 1991.
Of the 64 per cent of families with children under five who used some form of childcare services, just 1 per cent used a workplace scheme. A quarter used nursery schools or unpaid family and friends, 17 per cent used private or voluntary schemes, 11 per cent paid child minders or nannies, and 7 per cent used local authority schemes.
The figures also reveal that in 1991 64 per cent of people aged 60 to 69 had no educational qualifications, compared with 17 per cent of those aged 20 to 29.
Nearly 20,000 people aged 16 and above in a random sample of 10,000 private households around the country were interviewed between April 1991 and March 1992.
General Household Survey 1991, No 22; HMSO; pounds 20.70.