| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 425 |
42.6%
|
| 1 | Minor obstacle | 280 |
28.1%
|
| 2 | Moderate obstacle | 169 |
16.9%
|
| 3 | Major obstacle | 105 |
10.5%
|
| 4 | Very severe obstacle | 19 |
1.9%
|