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: [-36.122, 189.839, 169.722, 219.047, 70.243, -51.557, 242.129, 82.828, -67.704]

90.936