| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 545 |
33.4%
|
| 2 | between 1 and 2 yrs | 261 |
16%
|
| 3 | more than 2 yrs | 363 |
22.2%
|
| 4 | never | 439 |
26.9%
|
| 77 | don't know | 26 |
1.6%
|
| Sysmiss | 1102 |