| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don’t know (SPONTANEOUS) | 24 |
20%
|
| 1 | <1 month | 23 |
19.2%
|
| 2 | 1-3 months | 35 |
29.2%
|
| 3 | 4-6 months | 24 |
20%
|
| 4 | >6 months | 14 |
11.7%
|
| Sysmiss | 551 |