| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-3 | 2.92/5 | 4.65/5 |
| Vol 4-6 | 3.20/5 | 4.60/5 |
| Vol 7-9 | 3.32/5 | 4.71/5 |
| Vol 10-12 | 3.30/5 | 4.70/5 |
| Vol 13-15 | 3.11/5 | 4.64/5 |
| Vol 16-18 | 3.04/5 | 4.61/5 |
| Vol 19-21 | 3.12/5 | 4.66/5 |
| Vol 22-24 | 3.10/5 | 4.65/5 |
| Vol 25-27 | 3.36/5 | 4.74/5 |
| Vol 28-30 | 3.26/5 | 4.70/5 |
| Vol 31-33 | 2.99/5 | 4.62/5 |
| Vol 34-36 | 2.92/5 | 4.57/5 |
| Vol 37-39 | 2.96/5 | 4.66/5 |
| Vol 40-42 | 3.28/5 | 4.69/5 |
| Vol 43-45 | 3.28/5 | 4.71/5 |
| Vol 46-48 | 3.26/5 | 4.72/5 |
| Vol 49-51 | 2.69/5 | 4.62/5 |
| Vol 52-54 | 3.03/5 | 4.62/5 |
| Vol 55-57 | 3.00/5 | 4.62/5 |
| Vol 58-60 | 2.90/5 | 4.57/5 |
| Vol 61-63 | 3.15/5 | 4.70/5 |
| Vol 64-65 | 2.81/5 | 4.64/5 |
| Overall | 3.10/5 | 4.74/5 |