| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 401 |
40.2%
|
| 1 | Minor obstacle | 258 |
25.9%
|
| 2 | Moderate obstacle | 191 |
19.1%
|
| 3 | Major obstacle | 119 |
11.9%
|
| 4 | Very severe obstacle | 29 |
2.9%
|