| Value | Category |
|---|---|
| 1 | 0 |
| 2 | 99 |
| 3 | 300 |
| 4 | 400 |
| 5 | 500 |
| 6 | 600 |
| 7 | 1000 |
| 8 | 1500 |
| 9 | 2000 |
| 10 | 2300 |
| 11 | 2500 |
| 12 | 2800 |
| 13 | 3000 |
| 14 | 3500 |
| 15 | 4000 |
| 16 | 4300 |
| 17 | 5000 |
| 18 | 8000 |
| 19 | Don't know |
| 20 | Refused to answer |
| 21 | Outlier set to missing |
| 22 | Inconsistency set to missing |
| 23 | Not applicable |