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: [127.703, -82.203, 53.438]
Example Output: 32.979

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

Example Input: [-15.742, 162.92, 41.11, -19.597, 75.539, 41.934, 120.605]
Example Output:
58.11