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.

Example Input: [100.665, 40.782, 24.775, 206.105, 112.523, -96.309, 9.758, 149.054, 3.861, 235.974]
Example Output: 78.719

Example Input: [153.482, 150.917]
Example Output: 152.2

Example Input: [-76.341, -32.542, 58.871, 221.215, -3.84, -15.797, 117.105, 211.194]
Example Output:
59.983