The Ninth Revision of the International Classification of Diseases was approved by the 29th World Health Assembly in May 1976 to come into effect January 1, 1979. ICD-9 was adopted in Canada in 1979. ICD-9 is divided into two volumes: the Tabular List and the Alphabetic Index.
For more info see: http://www.cihi.ca/cihi-ext-portal/internet/en/document/standards+and+data+submission/standards/classification+and+coding/codingclass_icd9cm