| Value | Category | Cases | |
|---|---|---|---|
| 0 | No | 4018 |
22.6%
|
| 1 | Yes, took no drug | 13440 |
75.8%
|
| 8 | Don't know | 284 |
1.6%
|
| 9 | Missing | 286 | |
| Sysmiss | 86780 |