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: [99.023, 80.055, 174.922, 70.864, 175.406, -92.344, 183.968, 50.342, -13.817]

80.935