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: [2.81, 52.99, 55.279, 75.682, 73.835, 148.077, -54.162, 112.112]
Example Output: 58.328

Example Input: [80.346, 228.37, 18.978, -42.02]
Example Output: 71.419

Example Input: [4.225, 101.629, 62.852]
Example Output:
56.235