1. Centre for Demographic Studies (CED), Universitat Autònoma de Barcelona , Bellaterra , Spain
2. ICREA, Passeig Lluís Companys 23 , Barcelona , Spain
3. Department of Sociology and Anthropology, Tel Aviv University , Tel Aviv , Israel
4. Department of Economic, Financial and Actuarial Mathematics, University of Barcelona , Barcelona , Spain
5. Interdisciplinary Center on Population Dynamics, University of Southern Denmark , Odense , Denmark
6. Department of International Health, Johns Hopkins Bloomberg School of Public Health , Baltimore, MD , USA