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: [87.02, -25.654, -67.979, 52.368, 20.078, 160.939, 4.162, 205.092, -57.092, -68.35]
Example Output: 31.058

Example Input: [9.493, 8.117, 160.621, 71.858, 70.481]
Example Output:
64.114