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: [164.352, -97.553, 16.993, 212.683, -67.211, -48.332, 124.661, -49.122, -99.945]

17.392