| Progress | Difficulty | Peak |
|---|---|---|
| Vol 1-3 | 3.87/5 | 4.60/5 |
| Vol 4-6 | 4.09/5 | 4.63/5 |
| Vol 7-9 | 4.07/5 | 4.62/5 |
| Vol 10-12 | 4.15/5 | 4.66/5 |
| Vol 13-15 | 4.14/5 | 4.62/5 |
| Vol 16-18 | 4.18/5 | 4.65/5 |
| Vol 19-21 | 4.23/5 | 4.66/5 |
| Vol 22-24 | 4.18/5 | 4.64/5 |
| Vol 25-27 | 4.22/5 | 4.67/5 |
| Vol 28-30 | 4.22/5 | 4.66/5 |
| Vol 31-33 | 4.13/5 | 4.62/5 |
| Vol 34-36 | 4.13/5 | 4.63/5 |
| Vol 37-39 | 4.23/5 | 4.68/5 |
| Vol 40-42 | 4.21/5 | 4.66/5 |
| Vol 43-45 | 4.16/5 | 4.63/5 |
| Vol 46-48 | 4.18/5 | 4.64/5 |
| Vol 49-51 | 4.26/5 | 4.68/5 |
| Vol 52-54 | 3.96/5 | 4.64/5 |
| Vol 55-57 | 4.24/5 | 4.67/5 |
| Vol 58-60 | 4.17/5 | 4.68/5 |
| Vol 61-63 | 4.16/5 | 4.66/5 |
| Vol 64-66 | 4.20/5 | 4.65/5 |
| Vol 67-68 | 4.14/5 | 4.63/5 |
| Overall | 4.16/5 | 4.68/5 |