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: [-81.517, 126.001, 203.19, 236.819, 36.037, 152.691, -1.444, -37.296]
Example Output: 79.31

Example Input: [197.424, 44.178, 136.316, 246.48, 98.472, -31.327, 41.411]
Example Output: 104.708

Example Input: [-10.37, -75.168, 32.201, 51.419, 4.792, 175.575, -6.252, 121.019, -88.724, 9.185]
Example Output:
21.368