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: [227.404, 94.456, 233.241, 147.762, -31.667, -62.22, -93.912]
Example Output: 73.581

Example Input: [166.967, 154.381, -19.741, 157.124]
Example Output: 114.683

Example Input: [-17.613, 118.43, 177.279, 178.526]
Example Output:
114.156