| Value | Category | Cases | |
|---|---|---|---|
| 1 | About one month | 2 |
2.7%
|
| 2 | Few months (2-3 months) | 0 |
0%
|
| 3 | Less than one year | 1 |
1.4%
|
| 4 | More than one year | 70 |
95.9%
|
| Sysmiss | 9 |