| Value | Category | 
|---|---|
| 00 | NIU (not in universe) | 
| 10 | Primary or no formal education | 
| 20 | Some secondary | 
| 21 | Lower secondary | 
| 22 | Upper secondary | 
| 30 | Some vocational | 
| 40 | Some tertiary | 
| 41 | Third level, non-degree qualification | 
| 42 | Third level, degree or higher qualification | 
| 99 | Unknown |