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: [86.266, 108.683, -39.327, 154.207, -6.579, -69.091, -58.699, 75.526]

31.373