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: [-41.714, 218.588, 49.769, 142.519, 179.776, -99.226, 224.69, 191.642]
Example Output: 108.256

Example Input: [192.529, -67.249, 123.707, 41.987, 11.587, 202.189, 12.989]
Example Output: 73.963

Example Input: [-12.806, -99.514, 239.3]
Example Output:
42.327