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: [-57.148, -59.655, 208.462, 223.004, 100.684, 188.569]
Example Output: 100.653

Example Input: [-94.286, 148.737, 234.8, 148.972]
Example Output: 109.556

Example Input: [-47.084, -68.743, 242.164, -96.322, 21.453]
Example Output:
10.294