| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 48 |
3.6%
|
| -7 | Does not apply | 121 |
9.1%
|
| 0 | No obstacle | 395 |
29.5%
|
| 1 | Minor obstacle | 115 |
8.6%
|
| 2 | Moderate obstacle | 223 |
16.7%
|
| 3 | Major obstacle | 263 |
19.7%
|
| 4 | Very severe obstacle | 172 |
12.9%
|