| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1 year or less | 256 |
24.6%
|
| 2 | Between 1 and 2 years | 52 |
5%
|
| 3 | More than 2 years | 511 |
49%
|
| 4 | Never | 0 |
0%
|
| 77 | Don't know | 223 |
21.4%
|
| Sysmiss | 4971 |