| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.6%
|
| -7 | Does not apply | 9 |
1.4%
|
| 0 | No obstacle | 65 |
10.1%
|
| 1 | Minor obstacle | 110 |
17.1%
|
| 2 | Moderate obstacle | 192 |
29.8%
|
| 3 | Major obstacle | 174 |
27%
|
| 4 | Very severe obstacle | 91 |
14.1%
|