| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 212 |
14.8%
|
| 2 | between 1 and 2 yrs | 158 |
11.1%
|
| 3 | more than 2 yrs | 292 |
20.4%
|
| 4 | never | 741 |
51.9%
|
| 77 | don't know | 26 |
1.8%
|
| Sysmiss | 934 |