| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
20%
|
| 1 | One hour or less | 2 |
40%
|
| 12 | 1 |
20%
|
|
| 24 | 1 |
20%
|
|
| Sysmiss | 146 |