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: [183.473, -80.316, -30.328, 56.767, -57.165, 125.981, -74.7, 58.898, 131.679]

34.921