| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.8%
|
| -7 | Does not apply | 66 |
10.2%
|
| 0 | No obstacle | 126 |
19.5%
|
| 1 | Minor obstacle | 188 |
29.1%
|
| 2 | Moderate obstacle | 140 |
21.7%
|
| 3 | Major obstacle | 77 |
11.9%
|
| 4 | Very severe obstacle | 43 |
6.7%
|