| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 29 |
2.3%
|
| -7 | Does not apply | 14 |
1.1%
|
| 0 | No obstacle | 1025 |
82.7%
|
| 1 | Minor obstacle | 84 |
6.8%
|
| 2 | Moderate obstacle | 63 |
5.1%
|
| 3 | Major obstacle | 13 |
1%
|
| 4 | Very severe obstacle | 11 |
0.9%
|