| N˚ | Stress level | Amount | % | Real% | Total% |
| 1 | >111 low stress | 36 | 7.6 | 7.6 | 7.6 |
| 2 | 112 - 140 normal | 128 | 27.1 | 27.1 | 34.7 |
| 3 | 141 - 167 < high stress | 309 | 65.3 | 65.3 | 100.0 |
| 4 | Total | 473 | 100.0 | 100.0 |
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