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: [245.2, 202.565]
Example Output: 223.882

Example Input: [-59.526, 55.871, 118.248, 197.073]
Example Output: 77.916

Example Input: [-9.906, -62.574]
Example Output:
-36.24