| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 167 |
25.8%
|
| 2 | between 1 and 2 yrs | 85 |
13.1%
|
| 3 | more than 2 yrs | 100 |
15.5%
|
| 4 | never | 282 |
43.6%
|
| 77 | don't know | 13 |
2%
|
| Sysmiss | 455 |