Citation and credits

All materials provided in this website are free to view, download and use, under the terms of Licence Creative Commons Attribution 4.0 International (CC BY 4.0).

Please cite the data as follows: 

Human Multiple Births Database (Year). French Institute for Demographic Studies - INED (distributor). Extracted from: https://www.twinbirths.org (day/month/year).

If the data used come from a single source, please cite as follows: 

[Original data source, e.g. INSEE]. Data obtained via the Human Multiple Births Database. French Institute for Demographic Studies - INED (distributor). Extracted from: https://www.twinbirths.org (day/month/year).

Please consult the original data sources for further information on data usage and the appropriate citation. 

We thank the national statistical offices for providing the data and documentation. We are also grateful to their experts, who helped clarify the data and metadata:  

Australia The Australian Bureau of Statistics

Austria Statistics Austria

Canada Statistics Canada

Chile Instituto nacional de estadísticas

Czech Republic Czech Statistical Office

Denmark Statistics Denmark

Finland Statistics Finland

France INSEE

Germany Statistisches Bundesamt

Greece Hellenic Statistical Authority

Iceland Statistics Iceland

Italy ISTAT and Ministerio della Salute

Japan Ministry of Health Labour and Welfare

Lithuania Statistics Lithuania

New Zealand Statistics New Zealand

Netherlands Statistics Netherlands

Norway Statistics Norway

Republic of Korea Statistics Korea

Spain Instituto nacional de estadística

Sweden Statistics Sweden

Switzerland Federal Statistical Office

United States Centers for Disease Control and Prevention - National Center for Health Statistics

UK - England and Wales Office for National Statistics

UK - Scotland National Records of Scotland

Uruguay Ministerio de Salud Pública

 We are also grateful to researchers in certain universities, for their help and support with the historical data for some countries.