| Strength | <30 Years | ≥30 Years | Difference |
| <40% | 10.8% | 16.2% | −5.4% |
| 40% - 50% | 11.7% | 25.5% | −13.8% |
| 50% | 24.3% | 18.1% | 6.2% |
| 50% - 60% | 17.5% | 17.2% | 0.3% |
| 60% - 70% | 16.9% | 8.6% | 8.3% |
| >70% | 17.3% | 6.5% | 10.8% |
| Perceptual rate | 55.7% | 48.1% | 7.6% |