| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.7%
|
| -7 | Does not apply | 3 |
0.4%
|
| 0 | No obstacle | 378 |
53%
|
| 1 | Minor obstacle | 158 |
22.2%
|
| 2 | Moderate obstacle | 62 |
8.7%
|
| 3 | Major obstacle | 73 |
10.2%
|
| 4 | Very severe obstacle | 34 |
4.8%
|