| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 3 |
0.8%
|
| 0 | No obstacle | 192 |
53.5%
|
| 1 | Minor obstacle | 58 |
16.2%
|
| 2 | Moderate obstacle | 56 |
15.6%
|
| 3 | Major obstacle | 32 |
8.9%
|
| 4 | Very severe obstacle | 17 |
4.7%
|