| Value | Category | Cases | |
|---|---|---|---|
| 1 | Less than a year | 2494 |
34.6%
|
| 2 | 1 year to less than 3 years | 3429 |
47.6%
|
| 3 | 3 years or more | 1167 |
16.2%
|
| 9 | Unspecified | 116 |
1.6%
|
| Sysmiss | 227727 |