Characteristics | Prevalence (%)* | Rao-Scott χ2 | P values |
Age (year) | 89.05 | <0.0001 | |
≤13 | 31.0 (27.4–34.7) | ||
14 | 36.4 (33.6–39.3) | ||
15 | 43.5 (40.2–46.9) | ||
≥16 | 49.6 (46.0–53.1) | ||
Sex | 18.03 | <0.0001 | |
Boys | 45.4 (42.8–48.0) | ||
Girls | 39.1 (36.6–41.7) | ||
Areas | 0.06 | 0.81 | |
Urban | 43.0 (37.2–48.7) | ||
Rural | 42.1 (39.6–44.6) | ||
Types of school | 404.57 | <0.0001 | |
Middle school | 35.3 (33.0–37.6) | ||
Academic high school | 30.0 (27.2–32.9) | ||
Vocational high school | 73.5 (69.5–77.5) |
*Based on the weighted data.