I am studying widowhood from Greek censuses (age at widowhood, percent widows and widowers in various age groups, ratio of widows to widowers etc). Yet, my research is hampered by the fact that Greek censuses do not provide data on remarriages (age at first, second and third marriage). How can I calculate age at permanent widowhood without data on remarriage? And what exactly the age at widowhood from census data represents?