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: [93.048, 173.783, 88.736, -95.085, -77.155, -2.381, -84.313]
Example Output: 13.805

Example Input: [57.506, 172.357, 191.473, 131.849]
Example Output: 138.296

Example Input: [101.123, 196.452, -73.096, 45.159, 129.345, -60.469, -95.697]
Example Output:
34.688