| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-3 | 2.96/5 | 4.47/5 |
| Vol 4-6 | 2.89/5 | 4.42/5 |
| Vol 7-9 | 3.19/5 | 4.58/5 |
| Vol 10-12 | 3.42/5 | 4.57/5 |
| Vol 13-15 | 3.93/5 | 4.64/5 |
| Vol 16-18 | 4.14/5 | 4.70/5 |
| Vol 19-21 | 3.64/5 | 4.66/5 |
| Vol 22-24 | 3.56/5 | 4.58/5 |
| Vol 25-27 | 3.35/5 | 4.55/5 |
| Vol 28-30 | 3.53/5 | 4.62/5 |
| Vol 31-33 | 3.59/5 | 4.58/5 |
| Vol 34-36 | 3.97/5 | 4.61/5 |
| Vol 37-39 | 4.07/5 | 4.66/5 |
| Vol 40-42 | 3.64/5 | 4.65/5 |
| Vol 43-45 | 4.12/5 | 4.68/5 |
| Vol 46-48 | 3.39/5 | 4.65/5 |
| Vol 49-51 | 2.63/5 | 4.40/5 |
| Vol 52-54 | 3.26/5 | 4.57/5 |
| Vol 55-57 | 3.74/5 | 4.66/5 |
| Vol 58-60 | 3.47/5 | 4.58/5 |
| Vol 61-63 | 3.28/5 | 4.57/5 |
| Vol 64-66 | 2.93/5 | 4.46/5 |
| Vol 67-69 | 3.93/5 | 4.61/5 |
| Vol 70-72 | 3.17/5 | 4.55/5 |
| Vol 73-74 | 3.48/5 | 4.62/5 |
| Overall | 3.49/5 | 4.70/5 |