| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 yr or less | 188 |
26.3%
|
| 2 | between 1 and 2 yrs | 120 |
16.8%
|
| 3 | more than 2 yrs | 107 |
14.9%
|
| 4 | never | 301 |
42%
|
| 77 | don't know | 0 |
0%
|
| Sysmiss | 579 |