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: [85.011, -20.439, 195.195, 114.286]
Example Output: 93.513

Example Input: [97.816, -78.424]
Example Output: 9.696

Example Input: [-63.385, 42.584, -65.353, -20.816, 194.56, -46.15, 102.478, -81.403, 75.612, 177.171]
Example Output:
31.53