| Value | Category |
|---|---|
| 1 | Pre-primary education (ISCED 0) |
| 2 | Primary education (ISCED 1) |
| 3 | Lower secondary (ISCED 2) |
| 4 | Upper secondary (ISCED 3) |
| 5 | Post-secondary nontertiary education (ISCED 4) |
| 6 | First stage of tertiary education (ISCED 5) |
| 7 | Second stage of tertiary education (ISCED 6) |
| 9 | Don't know |