| Code | Definition | Number of Accessions |
| 1 | very low < 2 (g) | 3 |
| 2 | very low to low 2,0 - 6 (g) | 1 |
| 3 | low 6,1 - 10 (g) | |
| 4 | low to medium 10,1 - 14 (g) | |
| 5 | medium 14,1 - 18 (g) | |
| 6 | medium to high 18,1 - 22 (g) | |
| 7 | high 22,1 - 26 (g) | |
| 8 | high to very high 26,1 - 30 (g) | |
| 9 | very high > 30 (g) | |