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.

Ex Input:
[139.238, 225.164, -21.563, -22.339, -77.136, 96.772, -40.208, 121.974, 228.852]

Ex Output:
72.306


Ex Input:
[217.301, 19.358, -21.02, -51.249]

Ex Output:
41.098


Ex Input:
[-12.257, -2.874, 73.876, -68.286, 54.744, 123.908, 151.117, -62.612, -60.958, 91.189]

Ex Output:

28.785


