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: [192.74, 78.623, -5.937, 144.535]
Example Output: 102.49

Example Input: [74.43, 138.738, 114.237, 138.845, 188.957, 103.103, -43.988, -68.085, 157.274]
Example Output: 89.279

Example Input: [82.522, 85.774, 166.942, 104.506, -79.596, 164.142, -37.274, 71.002]
Example Output:
69.752