| Value | Category | Cases | |
|---|---|---|---|
| 1 | Flat | 2758 |
79.5%
|
| 2 | Roughly conical | 361 |
10.4%
|
| 3 | Gable (triangular cross-section) | 235 |
6.8%
|
| 4 | None of the above | 117 |
3.4%
|