1. Leverhulme Centre for Demographic Science, Department of Sociology, Nuffield College, University of Oxford, Oxford, UK
2. Population Research Center, Center on Aging and Population Sciences, The University of Texas at Austin, Austin, TX, USA
3. Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
4. Department of Sociology, University of Colorado Population Center, Institute of Behavioral Science, University of Colorado Boulder, Boulder, CO, USA
5. Carolina Population Center, Department of Sociology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA