| Z value range | 0 - 10 cm | 10 - 40 cm | 40 - 100 cm | 100 - 200 cm |
| Z ≤ −2.32 | 13.0% | 16.7% | 18.5% | 21.1% |
| −2.32 < Z ≤ −1.64 | 3.6% | 3.7% | 3.7% | 3.6% |
| −1.64 < Z ≤ −1.28 | 1.9% | 2.1% | 1.8% | 1.7% |
| −1.28 < Z ≤ 0 | 61.7% | 61.0% | 60.8% | 60.7% |
| 0 < Z ≤ 1.28 | 5.1% | 3.6% | 3.7% | 3.3% |
| 1.28 < Z ≤ 1.64 | 1.3% | 0.9% | 0.9% | 0.8% |
| 1.64 < Z ≤ 2.32 | 2.8% | 1.7% | 1.7% | 1.2% |
| Z > 2.32 | 10.6% | 8.9% | 8.9% | 7.6% |