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: [24.119, 239.006, 239.873, 236.27, 134.34]
Example Output: 174.722

Example Input: [126.136, -23.429, -25.125, -32.203, 36.405, 44.406, 147.828, -97.708, -69.793, 235.046]
Example Output: 34.156

Example Input: [-3.281, 84.204, -74.415, 151.616, 14.048, -98.313, 95.625, -79.981]
Example Output:
11.188