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: [-49.786, 238.124, -20.697, 32.014]
Example Output: 49.914

Example Input: [-79.748, 98.398, 55.667, 77.39, -20.719, 187.168, 142.334, 110.723]
Example Output: 71.402

Example Input: [117.3, 139.873, -78.605, -32.703, 13.848, 129.699, 125.607]
Example Output:
59.288