| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-2 | 2.92/5 | 4.23/5 |
| Vol 3-4 | 3.00/5 | 4.26/5 |
| Vol 5-6 | 3.16/5 | 3.97/5 |
| Vol 7-8 | 3.45/5 | 4.55/5 |
| Vol 9-10 | 3.42/5 | 4.46/5 |
| Vol 11-12 | 3.27/5 | 4.43/5 |
| Vol 13-14 | 3.50/5 | 4.40/5 |
| Vol 15-16 | 3.48/5 | 4.51/5 |
| Vol 17-18 | 3.40/5 | 4.38/5 |
| Vol 19-20 | 3.47/5 | 4.45/5 |
| Vol 21-22 | 3.74/5 | 4.66/5 |
| Vol 23-24 | 3.52/5 | 4.52/5 |
| Vol 25-26 | 3.29/5 | 4.41/5 |
| Vol 27 | 3.49/5 | 4.18/5 |
| Overall | 3.36/5 | 4.66/5 |