Proportion of out-of-marriage births by maternal generation and rank (%).

The count and description of the families of the Basque Country is done using various statistical sources. On the one hand, families are counted through the Population and Housing Census; on the other hand, the operation Demographic Survey (ED), of an intercensal and five-year periodicity, offers information on the formation of families, family size, preferences on the number and spacing of children, as well as numerous other characteristics, using the method of retrospective approximation to demographic phenomena. The count and description of the families of the Basque Country is done using various statistical sources. On the one hand, families are counted through the Population and Housing Census; on the other hand, the operation Demographic Survey (ED), of an intercensal and five-year periodicity, offers information on the formation of families, family size, preferences on the number and spacing of children, as well as numerous other characteristics, using the method of retrospective approximation to demographic phenomena.巴斯克地区家庭的数量统计与特征描述依托多种统计数据源开展。一方面，通过人口与住房普查完成家庭户数统计；另一方面，每五年开展一次的普查间人口调查项目（Demographic Survey，简称ED），采用人口现象回溯估算方法，可提供家庭形成、家庭规模、子女数量与生育间隔偏好，以及其他多项家庭相关特征的相关信息。