| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 253 |
37.9%
|
| 2 | between 1 and 2 yrs | 71 |
10.6%
|
| 3 | more than 2 yrs | 179 |
26.8%
|
| 4 | never | 131 |
19.6%
|
| 77 | don't know | 34 |
5.1%
|
| Sysmiss | 461 |