| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 315 |
48.7%
|
| 2 | between 1 and 2 yrs | 122 |
18.9%
|
| 3 | more than 2 yrs | 157 |
24.3%
|
| 4 | never | 41 |
6.3%
|
| 77 | don't know | 12 |
1.9%
|
| Sysmiss | 455 |