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: [-24.069, 49.942, -56.199, 147.337, 81.429, 198.62, -91.886, 33.842, -16.712, -51.661]
Example Output: 27.064

Example Input: [11.642, -39.595, 23.351, 168.447, 244.85, 108.958, 80.422, -14.774, 138.977]
Example Output: 80.253

Example Input: [-81.316, -66.29, 129.505, 64.587, 54.295, 97.979, -90.49, -48.845, 221.481, 25.455]
Example Output:
30.636