| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 56 |
5.8%
|
| 0 | No obstacle | 594 |
61.5%
|
| 1 | Minor obstacle | 159 |
16.5%
|
| 2 | Moderate obstacle | 98 |
10.1%
|
| 3 | Major obstacle | 44 |
4.6%
|
| 4 | Very severe obstacle | 15 |
1.6%
|