| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 year or less | 205 |
32.6%
|
| 2 | Between 1 and 2 years | 115 |
18.3%
|
| 3 | More than 2 years | 140 |
22.3%
|
| 4 | Never | 146 |
23.2%
|
| 77 | Don't know | 22 |
3.5%
|
| Sysmiss | 4810 |