| Value | Category | Cases | |
|---|---|---|---|
| 1 | Weekly | 31 |
2.8%
|
| 2 | Monthly | 181 |
16.3%
|
| 3 | Once a term | 426 |
38.4%
|
| 4 | Half a term | 35 |
3.2%
|
| 5 | Yearly | 117 |
10.6%
|
| 6 | Ad hoc | 142 |
12.8%
|
| 8 | Other | 176 |
15.9%
|
| Sysmiss | 477 |