| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 360 |
50.3%
|
| 2 | between 1 and 2 yrs | 153 |
21.4%
|
| 3 | more than 2 yrs | 169 |
23.6%
|
| 4 | never | 32 |
4.5%
|
| 77 | don't know | 2 |
0.3%
|
| Sysmiss | 579 |