Data on suicide rates are based on official registers on causes of death. They are standardised using the OECD population structure of 1980, accounting for changes in the age structure across countries and over time. Suicide rates are expressed in deaths per 100, 000 individuals.
Countries have different procedures for recording suicide as the underlying cause of death, despite the development of the International Statistical Classification of Diseases and Related Health Problems (ICD), and procedures may have changed over time. In addition, suicide may be under-reported because of societal stigma attached to suicide. This socio-cultural norm may vary across countries and over time.