| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 |
1.6%
|
| -7 | Does not apply | 3 |
0.5%
|
| 0 | No obstacle | 72 |
11.7%
|
| 1 | Minor obstacle | 123 |
20%
|
| 2 | Moderate obstacle | 159 |
25.9%
|
| 3 | Major obstacle | 169 |
27.5%
|
| 4 | Very severe obstacle | 79 |
12.8%
|