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: [16.426, 100.384, 116.375, -85.793, 156.604, -61.217, 203.053, -97.468, -18.549]

36.646