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: [85.011, -20.439, 195.195, 114.286]
Example Output: 93.513

Example Input: [-92.167, -67.984, -31.831, -21.057, 101.792, 114.116, 185.901, -25.874]
Example Output: 20.362

Example Input: [6.118, -43.196]
Example Output:
-18.539