| Value | Category | Cases | |
|---|---|---|---|
| 0 | Never | 40 |
4.9%
|
| 1 | Light | 608 |
74.1%
|
| 2 | Moderate | 143 |
17.4%
|
| 3 | Heavy | 29 |
3.5%
|
| Sysmiss | 628 |