This data is extracted as of Sep 7, 2017, with ratings up to Episode 182. The average difficulty level of an episode is the mean of the values of its levels with determined and non-variable ratings. Note that the calculation of means involve the total number of determined non-variable levels. Variable and undetermined levels are counted as if they do not contribute to the mean even though variable levels are considered hard. Episodes with more than 5 undetermined levels are undetermined. Episodes with an impossible level have an undefined value.