Definition: 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.
Input: [-75.704, -31.361, 79.286, 154.808, -82.324, 216.429, 54.074, -70.835, 164.234, 111.267]

51.987