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: [39.88, 58.489, 225.343, 105.008, 210.581, 35.577]
Example Output: 112.48

Example Input: [224.567, -42.213, 232.017]
Example Output: 138.124

Example Input: [95.57, 167.946, -18.475, 52.08]
Example Output:
74.28