| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 11 |
3.1%
|
| 0 | No obstacle | 152 |
42.2%
|
| 1 | Minor obstacle | 55 |
15.3%
|
| 2 | Moderate obstacle | 62 |
17.2%
|
| 3 | Major obstacle | 48 |
13.3%
|
| 4 | Very severe obstacle | 28 |
7.8%
|