| Value | Category |
|---|---|
| 0 | Did not go to school |
| 1 | first grade |
| 2 | Second grade |
| 3 | Third grade |
| 4 | Fourth grade |
| 5 | Fifth grade |
| 6 | Sixth grade |
| 7 | Seventh grade |
| 8 | Eighth grade |
| 9 | Nineth grade |
| 10 | Tenth grade |
| 11 | Eleventh grade |
| 12 | Twelfth grade |
| 13 | Post high school but less than bachelor |
| 14 | Bachelor or higher degree |