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: [67.796, -84.772, 182.833, 87.455, 21.435, 58.087, 38.98, -18.137, 246.089]

66.641