Définition
The fertility rate at a given age is the number of children born alive to women of that age during the year as a proportion of the average annual population of women of the same age.
By extension, the fertility rate is the ratio between the number of live births in a year and the whole female population of childbearing age (average number of women between 15 and 50 years of age over the year). Unlike total period fertility, the fertility rate is partly dependent on trends in the age structure of women between the ages of 15 and 50.