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: [-32.557, -70.922, 191.786, 244.222]
Example Output: 83.132

Example Input: [152.683, 147.968, 62.877, -44.254, 4.344]
Example Output: 64.724

Example Input: [23.599, -32.069, 215.673, 238.27]
Example Output:
111.368