Prevalence of e-cigarette and cigarette use (% of adolescent population) at two time points
| E-cigarettes (%) | Cigarettes (%) | |||
|---|---|---|---|---|
| Frequency | Time 1 | Time 2 | Time 1 | Time 2 |
| Never used | 69 | 62 | 85 | 79 |
| Used 1–2 times | 9 | 10 | 6 | 10 |
| Used 3–4 times | 12 | 15 | 4 | 5 |
| Used few times past year | 2 | 5 | 2 | 2 |
| Used few times past month | 3 | 3 | 2 | 2 |
| Used few times past week | 3 | 2 | 1 | 1 |
| Use every day | 2 | 3 | <1 | 1 |
Time 1 N=2338; Time 2 N=2239.