| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 461 |
32.3%
|
| 2 | between 1 and 2 yrs | 307 |
21.5%
|
| 3 | more than 2 yrs | 438 |
30.7%
|
| 4 | never | 180 |
12.6%
|
| 77 | don't know | 43 |
3%
|
| Sysmiss | 934 |