| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
1.1%
|
| -7 | Does not apply | 9 |
0.9%
|
| 0 | No obstacle | 480 |
48.1%
|
| 1 | Minor obstacle | 214 |
21.4%
|
| 2 | Moderate obstacle | 131 |
13.1%
|
| 3 | Major obstacle | 100 |
10%
|
| 4 | Very severe obstacle | 53 |
5.3%
|