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: [228.031, -85.617, 36.164]
Example Output: 59.526

Example Input: [73.331, 85.459, 59.798, -35.019]
Example Output: 45.892

Example Input: [-55.711, 55.72, 40.975, 209.662, -74.651, 125.271, 36.67, -2.016]
Example Output:
41.99