"In 2010, for people aged 14 years or older who had used cannabis in the previous 12 months, only 7.2% had not used any other listed drugs while using cannabis (Table 6.10). Males were more likely than females to use any drug in combination with cannabis except for over-the-counter pain-killers, which had the same proportion for both sexes (2.9%). The most common drugs that were mixed with cannabis were alcohol (85.2%) and tobacco (68.8%). Ecstasy was the most common illicit drug to be used at the same time as cannabis (23.9%)."

Source

Australian Institute of Health and Welfare 2011. 2010 National Drug Strategy Household Survey report. Drug statistics series no. 25. Cat. no. PHE 145. Canberra: AIHW, p. 113.
http://www.aihw.gov.au/WorkAr…