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: [-72.984, 128.607, 6.477, -21.627, 234.268, 16.279, 51.947, 104.513, 182.928]

70.045