Table 1.

Percentages of RWI at least once in past year at Waves 1 to 4 (n = 2,659)

Variable	Weighted %	SE	[95% CI]	Min.	Max.
Wave 1	32.92	1.75	[29.49, 36.35]	32.45	33.33
Wave 2	24.09	1.95	[20.26, 27.92]	23.22	25.14
Wave 3	26.72	1.63	[23.53, 29.91]	25.63	28.22
Wave 4	26.11	1.71	[22.74, 29.47]	24.12	27.80

Notes: Min. and max. indicate the minimum/maximum computed weighted % from the 50 imputed data sets. RWI = riding with an alcohol/drug-impaired driver; CI = confidence interval.