| Elevation interval (m) | Average altitude (m) | Area (km2) | Cumulative area (km2) | Cumulative area (%) |
| <300 | 132 | 27 | 27 | 18.8 |
| 300 - 600 | 474 | 56 | 83 | 57.6 |
| 600 - 900 | 722 | 29 | 112 | 77.8 |
| 900 - 1200 | 1029 | 13 | 125 | 86.8 |
| 1200 - 1500 | 1384 | 8 | 133 | 92.4 |
| 1500 - 1800 | 1638 | 8 | 141 | 97.9 |
| >1800 | 1912 | 3 | 144 | 100 |