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: [-89.59, -15.783, 35.306, 46.851, 97.275, 19.027, 200.372, 62.551]
Example Output: 44.501

Example Input: [13.21, 76.551, 51.016, 230.763, 149.792, 157.216, 117.414, 144.272, 5.805, 118.165]
Example Output: 106.42

Example Input: [126.801, 221.128, 190.286, -15.375]
Example Output:
130.71