| Value | Category | Cases | |
|---|---|---|---|
| 1 | Monthly | 41 |
1.7%
|
| 2 | Quarterly | 405 |
16.9%
|
| 3 | Bi-quarterly | 19 |
0.8%
|
| 4 | Half yearly | 151 |
6.3%
|
| 5 | Yearly | 364 |
15.2%
|
| 6 | Never | 1420 |
59.2%
|
| Sysmiss | 650 |