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: [77.445, 104.353, -42.235, 111.327, 166.266, -70.294, -92.342, 132.12, 142.664]

58.812