| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -8 | Refusal (spontaneous) | 0 |
0%
|
| 1 | One year or less | 1 |
10%
|
| 2 | 4 |
40%
|
|
| 3 | 1 |
10%
|
|
| 7 | 1 |
10%
|
|
| 10 | 2 |
20%
|
|
| 20 | 1 |
10%
|
|
| Sysmiss | 1653 |