Table 2

Trends in youth smoking prevalence: California campaign, 1990 to present

		Grades		Reported 30 day smoking prevalence				Change in smoking prevalence 1993 to 1995			Reported 30 day smoking prevalence 1997			Change in smoking prevalence 1995 to 1997
		Grades		1993	1995			Change in %	Relative risk		Reported 30 day smoking prevalence 1997			95% CI for relative risk	Change in %	Relative risk	95% CI
California	8th	12.0	12.0			0	1.00	0.74 to 1.35		14.0		+2.0	1.17	0.83 to 1.54
US	8th	16.7	19.1			+2.4^2-150	1.14^2-150	1.05 to 1.25		19.4		+0.3	1.02	0.94 to 1.10

California	10th	18.0	18.0			0	1.00	0.78 to 1.29		19.0		+1.0	1.06	0.82 to 1.36
US	10th	24.7	27.9			+3.2^2-150	1.13^2-150	1.05 to 1.21		29.8		+1.9	1.07	0.99 to 1.14

Source: Monitoring the Future California— specific data published in final report: independent evaluation of the California tobacco control prevent and education program: wave 1 data, 1996 to 1997. Monitoring the Future data also used for national (USA) comparisons.^65,66
↵2-150 p ⩽ 0.05