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: [140.596, 20.144, 149.242, 92.447, -92.97, 137.685, 118.721, 153.251, 109.455]

92.063