Synthetic fertility index and middle age at maternity in the Basque Country by birth range, historical territory and region, by year.

The study of demographic phenomena Mortality, Bridality, Fertility and Migration requires the elaboration of a series of synthetic indicators and indices, and this is the objective of the statistical operation Demographic Indicators (ID) in its annual scope. The Synthetic Fertility Index according to the mean age at maternity, the Synthetic Nuptiality Index according to the mean age at bridality, or the life expectancy at birth are the result of this statistical operation of synthesis; the results are disseminated by sex and region in the field of the Basque Country.