| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply (spontaneous) | 25 |
1.6%
|
| 0 | No obstacle | 1465 |
93.1%
|
| 1 | Minor obstacle | 64 |
4.1%
|
| 2 | Moderate obstacle | 16 |
1%
|
| 3 | Major obstacle | 2 |
0.1%
|
| 4 | Very severe obstacle | 1 |
0.1%
|