| Value | Category | Cases | |
|---|---|---|---|
| -2 | don't know | 20 |
21.7%
|
| -1 | refuse | 0 |
0%
|
| 0 | 1 |
1.1%
|
|
| 1 | Kg | 16 |
17.4%
|
| 2 | M3 | 6 |
6.5%
|
| 3 | Balloon | 44 |
47.8%
|
| 4 | per month | 5 |
5.4%
|
| Sysmiss | 957 |