| Value | Category | Cases | |
|---|---|---|---|
| 1 | Traffic | 538 |
14.9%
|
| 2 | Airplanes | 2 |
0.1%
|
| 3 | Quarries/Stone cutting | 13 |
0.4%
|
| 4 | Construction activities | 35 |
1%
|
| 5 | Industrial activities | 82 |
2.3%
|
| 6 | Other, specify | 234 |
6.5%
|
| Sysmiss | 2703 |