| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 7 |
1.9%
|
| 0 | No obstacle | 183 |
51%
|
| 1 | Minor obstacle | 75 |
20.9%
|
| 2 | Moderate obstacle | 69 |
19.2%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 6 |
1.7%
|