| Category | 1st grade | 3rd grade | 5th grade | |||
|---|---|---|---|---|---|---|
| cut-off1) / | Prevalence | cut-off / | Prevalence | cut-off / | Prevalence | |
| Total | 133 / 1,577 | 8.4% | 92 / 1,461 | 6.3% | 61 / 1,227 | 5.0% |
| Boys | 50 / 807 | 6.2% | 39 / 737 | 5.3% | 23 / 631 | 3.6% |
| Girls | 83 / 770 | 10.8% | 53 / 724 | 7.3% | 38 / 596 | 6.4% |
| 9.36 | 2.55 | 4.84 | ||||