|
| D30 | D40 | D50 | D60 | D70 |
| Mean | 9500 | 10,800 | 16,000 | 18,500 | 21,000 |
| Minimum | 6000 | 7500 | 12,600 | 15,600 | 18,000 |
|
| Very weak | Weak | Medium | Strong | Very strong |