| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 319 |
49.3%
|
| 2 | between 1 and 2 yrs | 107 |
16.5%
|
| 3 | more than 2 yrs | 117 |
18.1%
|
| 4 | never | 86 |
13.3%
|
| 77 | don't know | 18 |
2.8%
|
| Sysmiss | 455 |