| Value | Category | Cases | |
|---|---|---|---|
| 0 | 0. No difficulty | 2609 |
37%
|
| 1 | 1. Minor difficulty | 3960 |
56.1%
|
| 2 | 2. Big difficulty | 293 |
4.2%
|
| 3 | 3. Not applicable | 195 |
2.8%
|