| Value | Category | Cases | |
|---|---|---|---|
| 0 | Never | 6 |
3.2%
|
| 1 | Light | 136 |
72.3%
|
| 2 | Moderate | 41 |
21.8%
|
| 3 | Heavy | 5 |
2.7%
|
| Sysmiss | 2012 |