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: [-69.698, 181.415, -43.045, 160.857]
Example Output: 57.382

Example Input: [-6.099, 142.31]
Example Output: 68.106

Example Input: [-92.32, -37.929, -9.194, 21.353, 35.008, 201.653, -27.303, 189.928, 109.737]
Example Output:
43.437

