Source: Office for National Statistics – Births in England and Wales: summary tables
- The total fertility rate is the average number of live children that a group of women would bear if they experienced the age-specific fertility rates of the calendar year in question throughout their childbearing lifespan.
- The mean is standardised and shows the mean age of the mothers who had births in the year in question. This measure allows fertility trends to be separated out from the effects of changes in the population’s age structure over time. Standardised means are calculated using rates per 1,000 female population by single year of age.
- Births registered to a same sex couple in a marriage/civil partnership (881 in 2015) are included with marital births while births registered to a same sex couple outside a marriage/civil partnership (339 in 2015) are included with births outside marriage. Same-sex female couples have been able to register the birth of a child as mother and second parent since 1 September 2009.