| Value | Category | Cases | |
|---|---|---|---|
| 1 | Every year | 379 |
9.4%
|
| 2 | Once every three years | 128 |
3.2%
|
| 3 | Once over three years | 68 |
1.7%
|
| 4 | No increase | 2435 |
60.7%
|
| 5 | Doesn't know | 763 |
19%
|
| 6 | Not applicable | 222 |
5.5%
|
| 9 | Missing value | 17 |
0.4%
|