| Value | Category | Cases | |
|---|---|---|---|
| 0 | less than a year | 251 |
54%
|
| 1 | one year | 125 |
26.9%
|
| 2 | two years | 38 |
8.2%
|
| 3 | three years | 3 |
0.6%
|
| 4 | four years | 6 |
1.3%
|
| 5 | five years | 6 |
1.3%
|
| 6 | six years | 6 |
1.3%
|
| 7 | seven years | 1 |
0.2%
|
| 8888 | don't know | 29 |
6.2%
|
| Sysmiss | 1 |