| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.7%
|
| -7 | Does not apply | 41 |
6.9%
|
| 0 | No obstacle | 122 |
20.4%
|
| 1 | Minor obstacle | 132 |
22.1%
|
| 2 | Moderate obstacle | 146 |
24.4%
|
| 3 | Major obstacle | 135 |
22.6%
|
| 4 | Very severe obstacle | 18 |
3%
|