| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.5%
|
| -7 | Does not apply | 20 |
5%
|
| 0 | No obstacle | 104 |
25.9%
|
| 1 | Minor obstacle | 109 |
27.1%
|
| 2 | Moderate obstacle | 52 |
12.9%
|
| 3 | Major obstacle | 69 |
17.2%
|
| 4 | Very severe obstacle | 46 |
11.4%
|