| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 183 |
51.7%
|
| 1 | Minor obstacle | 76 |
21.5%
|
| 2 | Moderate obstacle | 64 |
18.1%
|
| 3 | Major obstacle | 26 |
7.3%
|
| 4 | Very severe obstacle | 4 |
1.1%
|