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: [-51.496, 56.177, 55.554, -17.425, -6.185, 3.721]
Example Output: 6.724

Example Input: [93.72, 13.366, -44.452, -29.011, 56.593, 5.272, -20.162, 160.282, 44.017]
Example Output: 31.069

Example Input: [126.003, -76.128, -30.337, 74.801, 65.633, 172.839, 187.609, 103.233]
Example Output:
77.957