Definition: In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.
Input: [-40.759, 81.651, -9.157, -89.35, 27.604, -62.325, 100.805, 111.715]

15.023