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: [-40.016, 117.495]
Example Output: 38.74

Example Input: [246.278, 103.84, 214.867, -73.466, 230.048, -72.322, 172.891, 212.306, -78.335, 122.406]
Example Output: 107.851

Example Input: [-41.085, 179.367, -47.961, 211.743, 242.631, 167.835, 165.969, 48.244]
Example Output:
115.843