| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
25%
|
| 1 | One hour or less | 1 |
25%
|
| 3 | 1 |
25%
|
|
| 24 | 1 |
25%
|
|
| Sysmiss | 357 |