| Code | Definition | Number of Accessions |
| 1 | very narrow | 76 |
| 2 | (1= very narrow, 9= very wide) | 347 |
| 3 | (1= very narrow, 9= very wide) | 330 |
| 4 | (1= very narrow, 9= very wide) | 347 |
| 5 | (1= very narrow, 9= very wide) | 358 |
| 6 | (1= very narrow, 9= very wide) | 324 |
| 7 | (1= very narrow, 9= very wide) | 228 |
| 8 | (1= very narrow, 9= very wide) | 54 |
| 9 | very wide | 41 |