| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 178 |
26.6%
|
| 2 | between 1 and 2 yrs | 83 |
12.4%
|
| 3 | more than 2 yrs | 291 |
43.6%
|
| 4 | never | 98 |
14.7%
|
| 77 | don't know | 18 |
2.7%
|
| Sysmiss | 461 |