The data are based on the Register of Induced Abortions and Sterilisations at National Institute for Health and Welfare, which receives the data from the operating physician. Data on sterilisations have been collected since 1935.
Official Statistics of Finland (OSF):
Helsinki: National Institute for Health and Welfare (THL) [referred: 24.5.2013].
Access method: http://www.stat.fi/til/stert/meta_en.html.