| Value | Category | Cases | |
|---|---|---|---|
| 1 | Vacuum truck | 461 |
29.8%
|
| 2 | Transfer into a hole | 830 |
53.7%
|
| 3 | Rainwater,river | 55 |
3.6%
|
| 4 | Other | 198 |
12.8%
|
| 9 | 2 |
0.1%
|
|
| Sysmiss | 2422 |