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: [-81.578, 94.601, 150.275, 111.758, 14.779, -87.854, 72.227, 142.99, 200.847]

68.672