| Value | Category | 
|---|---|
| -9 | -9. Don't know | 
| -5 | -5. Refused | 
| -3 | -3. Not applicable | 
| 1 | 1. 15-17 years | 
| 2 | 2. 18-19 years | 
| 3 | 3. 20-24 years | 
| 4 | 4. 25-29 years | 
| 5 | 5. 30-34 years | 
| 6 | 6. 35-39 years | 
| 7 | 7. 40-44 years | 
| 8 | 8. 45-49 years | 
| 9 | 9. 50-54 years | 
| 10 | 10. 55-59 years | 
| 11 | 11. 60-64 years | 
| 12 | 12. 65+ years |