| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-2 | 2.70/5 | 4.39/5 |
| Vol 3-4 | 3.58/5 | 4.57/5 |
| Vol 5-6 | 3.88/5 | 4.59/5 |
| Vol 7-8 | 3.30/5 | 4.55/5 |
| Vol 9-10 | 2.90/5 | 4.45/5 |
| Vol 11-12 | 3.07/5 | 4.46/5 |
| Vol 13-14 | 3.12/5 | 4.49/5 |
| Vol 15-16 | 3.48/5 | 4.54/5 |
| Vol 17-18 | 3.26/5 | 4.51/5 |
| Vol 19-20 | 3.64/5 | 4.58/5 |
| Vol 21-22 | 3.63/5 | 4.61/5 |
| Vol 23-24 | 3.88/5 | 4.64/5 |
| Vol 25-26 | 3.54/5 | 4.55/5 |
| Vol 27-28 | 3.64/5 | 4.61/5 |
| Overall | 3.40/5 | 4.64/5 |