| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 163 |
27.2%
|
| 1 | Minor obstacle | 172 |
28.7%
|
| 2 | Moderate obstacle | 176 |
29.3%
|
| 3 | Major obstacle | 77 |
12.8%
|
| 4 | Very severe obstacle | 11 |
1.8%
|