| Value | Category | Cases | |
|---|---|---|---|
| 1 | 1. Very far from the surface (>1 meter) | 1055 |
25.9%
|
| 2 | 2. Within 1 meter | 379 |
9.3%
|
| 3 | 3. Very close to the surface or full | 114 |
2.8%
|
| 97 | 97. Not Asked | 1387 |
34%
|
| 99 | 99. Observation not possible | 1144 |
28%
|
| Sysmiss | 35 |