| Value | Category | Cases | |
|---|---|---|---|
| 1 | straw | 1812 |
3.7%
|
| 2 | mud | 253 |
0.5%
|
| 3 | wood | 6911 |
14.1%
|
| 4 | steel ( galvanised) | 239 |
0.5%
|
| 5 | reinforced concrete | 39388 |
80.1%
|
| 6 | tiles | 80 |
0.2%
|
| 7 | other | 503 |
1%
|