Table 1.

Sample Characteristics at Wave of Recruitment for Each Respondent

%	Canada	United States	United Kingdom	Australia	Overall
	n = 5545	n = 7832	n = 5421	n = 5033	n = 23 831
Age (y)
18–24	12.46	13.52	13.14	14.23	13.34
25–39	32.04	29.97	32.70	35.52	32.23
40–54	35.37	34.98	29.93	32.84	33.47
55+	20.14	21.53	24.24	17.41	20.96
Gender: female	46.21	46.33	49.10	45.43	46.75
Ethnicity: majority	88.84	78.84	94.17	87.51	86.47
Annual household income
Low	25.80	37.63	28.76	25.51	30.33
Moderate	32.95	32.31	32.16	32.95	32.98
High	30.83	24.50	29.62	34.74	29.28
No answer	8.58	5.57	9.46	6.79	7.41
Education
Low	49.39	47.66	58.73	64.46	54.08
Moderate	35.81	38.07	26.95	22.23	31.71
High	14.37	14.17	13.55	12.97	13.83
No answer	0.43	0.10	0.76	0.34	0.38
HSIa (mean (SEb))	2.89 (0.02)	2.84 (0.02)	2.66 (0.02)	2.95 (0.03)	2.83 (0.01)
Wave of recruitment
Wave 1	37.07	25.09	41.67	42.57	35.30
Wave 2	8.59	8.10	4.11	4.63	6.58
Wave 3	9.16	10.65	10.38	9.78	10.06
Wave 4	8.77	8.81	8.95	6.77	8.41
Wave 5	10.13	9.04	10.42	12.80	10.39
Wave 6	9.26	8.53	9.11	9.98	9.13
Wave 7	5.61	4.46	6.25	2.24	4.67
Wave 8c	3.45	4.32	0.00	3.84	3.03
Wave 9	7.98	21.00	9.12	7.40	12.42
Time-in-sample
1 wave	39.06	52.40	39.34	35.97	41.90
2 waves	22.10	20.61	22.83	22.61	22.01
3 waves	14.05	11.10	14.55	14.60	13.52
4 waves	9.45	6.89	9.53	10.51	9.05
5 waves	5.95	4.03	5.95	6.48	5.57
6 waves	4.08	2.38	3.57	4.20	3.54
7 waves	2.71	1.39	2.29	2.91	2.31
8 waves	1.71	0.82	1.25	1.73	1.37
9 waves	0.89	0.38	0.68	1.00	0.73

Data are weighted.

^aHSI = Heaviness of Smoking Index.

^bSE = standard error.

^cThere was no replenishment at wave 8 in the United Kingdom due to resource constraints.