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: [221.859, 56.728, 114.275, 71.768, -91.382, 134.583, 43.599, 90.369]

80.225