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: [-48.061, 26.658, -86.358, 1.313, 210.341, 116.85, 156.805, 186.555, 14.375]

64.275