Overall, 70% of first cohabitations, which did not end in marriage began by the age of 25.

• First cohabitations which did not end in marriage were most likely to begin when people were aged 20 to 24 (41%).

• Women were more likely than men to begin their first completed cohabitation at a younger age, 36% began their first cohabiting union by the age of 19 compared with 21% of men.

The age at which people started their first completed cohabitation also varied with the year in which the cohabitation began. For both men and women, those starting their first cohabitation between 1990 and 2002 tended to start at an older age than those who started their first completed cohabitation in the 1960-70s. For cohabitations started in the 1960-70s, 41% of women started a first cohabiting union by the age of 19 compared with 36% between 1990 and 2002; the equivalent figures for men were 27% and 16%.