| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.7%
|
| -7 | Does not apply | 8 |
1.1%
|
| 0 | No obstacle | 189 |
24.9%
|
| 1 | Minor obstacle | 193 |
25.4%
|
| 2 | Moderate obstacle | 252 |
33.2%
|
| 3 | Major obstacle | 88 |
11.6%
|
| 4 | Very severe obstacle | 25 |
3.3%
|