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: [-61.563, 49.659, 125.562, 130.542, 75.232, 197.442, 175.182, 54.736, 210.833, 65.27]
Example Output: 102.289

Example Input: [-6.305, 138.079, 112.522, 52.257, -2.129]
Example Output: 58.885

Example Input: [108.822, 139.139, 130.938, 100.996, 155.361, 8.752, 221.639, -12.877]
Example Output:
106.596