| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply is a floor in a building (spontaneous) | 8 |
2.3%
|
| 0 | 338 |
96%
|
|
| 99 | 1 |
0.3%
|
|
| 100 | 1 |
0.3%
|