| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 31 |
2.5%
|
| -7 | Does not apply | 44 |
3.6%
|
| 0 | No obstacle | 1023 |
82.6%
|
| 1 | Minor obstacle | 79 |
6.4%
|
| 2 | Moderate obstacle | 42 |
3.4%
|
| 3 | Major obstacle | 14 |
1.1%
|
| 4 | Very severe obstacle | 6 |
0.5%
|