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: [102.553, 221.594, -69.406, 192.534, 139.703, -38.208, 228.963, 32.921]
Example Output: 101.332

Example Input: [-19.13, 98.86, 158.686, 230.23]
Example Output: 117.161

Example Input: [149.512, 106.154, 30.468]
Example Output:
95.378