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: [-31.181, -2.589, 51.847, 105.073, -66.206, 162.609, -12.31, 190.92, -33.967, 222.499]

58.669