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: [-23.938, 180.002, 99.059, 120.407, 49.388, -89.173, 13.758, 167.814, 80.522]

66.427