| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.9%
|
| -7 | Does not apply is a floor in a building (spontaneous) | 15 |
1.9%
|
| 0 | 738 |
95.6%
|
|
| 20 | 1 |
0.1%
|
|
| 40 | 1 |
0.1%
|
|
| 60 | 1 |
0.1%
|
|
| 100 | 9 |
1.2%
|