Table 4.

Clustering of substance use: percentages of students (aged 13–16) using alcohol in the last month and/or smoking last week and/or using cannabis ever in the survey of 2005 and 2009 (%)

	2005	2009
	(N = 1,850)	(N = 2,044)
		a
No alcohol, no smoking, no cannabis	36.6	52.6
No alcohol, smoking, no cannabis	0.5	0.5
No alcohol, no smoking, cannabis	0.6	1.7
No alcohol, smoking, cannabis	0.5	0.9
Alcohol, no smoking, no cannabis	38.8	27.2
Alcohol, smoking, no cannabis	2.5	2.6
Alcohol, no smoking, cannabis	10.1	6.6
Alcohol, smoking, cannabis	10.4	7.9

^acompared with Chi-squared test; p <0.05