| Value | Category | Cases | |
|---|---|---|---|
| 1 | Less than one year | 17 |
3.2%
|
| 2 | One to two years | 42 |
7.8%
|
| 3 | Two to three years | 51 |
9.5%
|
| 4 | Four to five years | 79 |
14.7%
|
| 5 | Five to ten years | 129 |
23.9%
|
| 6 | Ten to twenty years | 131 |
24.3%
|
| 7 | More than twenty years | 90 |
16.7%
|
| Sysmiss | 467 |