I would like to point out an error in your set of data. You can't take the total experience and divide it by the amount of experience per yew. Most of that experience had to have been gained by cutting normal trees, oaks, and willows because they wouldn't be able to cut yews until level 60. So your data isn't correct. You actual calculation should look like: Total experience - (exp for level 60 x # of autoers) / exp per yew = # of yews