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: [-81.785, -44.121]
Example Output: -62.953

Example Input: [125.332, 80.443]
Example Output: 102.887

Example Input: [174.943, -19.337, 67.246, 202.457, 191.304, 67.278, 61.986]
Example Output:
106.554

