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: [-33.746, 231.27, 122.704, -25.907, -56.96]
Example Output: 47.472

Example Input: [96.706, 239.918, 73.299, 68.184, 233.512, -76.407]
Example Output: 105.869

Example Input: [152.826, 128.15, 58.05, 117.052, 18.302, 0.717]
Example Output:
79.183