| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 492 |
49.4%
|
| 2 | between 1 and 2 yrs | 171 |
17.2%
|
| 3 | more than 2 yrs | 202 |
20.3%
|
| 4 | never | 85 |
8.5%
|
| 77 | don't know | 45 |
4.5%
|
| Sysmiss | 648 |