| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 175 |
48.7%
|
| 1 | Minor obstacle | 93 |
25.9%
|
| 2 | Moderate obstacle | 56 |
15.6%
|
| 3 | Major obstacle | 27 |
7.5%
|
| 4 | Very severe obstacle | 7 |
1.9%
|