| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 27 |
4.4%
|
| 0 | No obstacle | 158 |
25.7%
|
| 1 | Minor obstacle | 140 |
22.8%
|
| 2 | Moderate obstacle | 138 |
22.4%
|
| 3 | Major obstacle | 111 |
18%
|
| 4 | Very severe obstacle | 40 |
6.5%
|