| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 35 |
8.7%
|
| 0 | No obstacle | 186 |
46.3%
|
| 1 | Minor obstacle | 78 |
19.4%
|
| 2 | Moderate obstacle | 45 |
11.2%
|
| 3 | Major obstacle | 26 |
6.5%
|
| 4 | Very severe obstacle | 31 |
7.7%
|