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: [205.819, 18.369, 221.68, 47.234, 188.28, -30.555, -86.475, 92.192, -33.895]

69.183