1. Department of Social Research, University of Helsinki, Helsinki, Finland; Max Planck Institute for Demographic Research, Rostock, Germany
2. Max Planck Institute for Demographic Research, Rostock, Germany; INVEST Flagship Center, University of Turku, Turku, Finland
3. Department of Population and Welfare, Statistics Sweden, Stockholm, Sweden
4. ROCKWOOL Foundation, Copenhagen, Denmark; Swedish Institute for Social Research, Stockholm University, Stockholm, Sweden
5. Research Department, Statistics Norway, Oslo, Norway