| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
1.6%
|
| -7 | Does not apply | 2 |
0.5%
|
| 0 | No obstacle | 110 |
29.2%
|
| 1 | Minor obstacle | 61 |
16.2%
|
| 2 | Moderate obstacle | 118 |
31.3%
|
| 3 | Major obstacle | 40 |
10.6%
|
| 4 | Very severe obstacle | 40 |
10.6%
|