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: [63.996, 173.103, 9.333, 165.098, 34.132, 124.734, 229.372, -26.178, -31.59, 112.215]

85.422