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: [212.195, 152.682, 81.687, 54.129, 77.845, 220.624, 156.819, 188.596, 63.238]

134.202