1. University of Oxford, OX1 2JD Oxford, UK
2. Nuffield College, OX1 1NF Oxford, UK
3. Leverhulme Centre for Demographic Science, OX1 1JD Oxford, UK
4. French Institute for Demographic Studies (INED), 75980 Paris, France
5. French Museum of Natural History (UMR 7206), 75005 Paris, France
6. Global Data Lab, Institute for Management Research, Radboud University, 6525 XZ Nijmegen, the Netherlands