1. Population Research Centre, Faculty of Spatial Sciences, University of Groningen, Landleven 1, 9747 Groningen, The Netherlands
2. Center for Demographic Studes, Centres de Recerca de Catalunya (CERCA), Carrer de Ca n’Altayó, Edifici E2, 08193 Bellaterra, Spain
3. Netherlands Interdisciplinary Demographic Institute, KNAW/University of Groningen, Lange Houtstraat 19, 2511 The Hague, The Netherlands