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: [131.411, 161.606, 206.651, 7.559, 31.125, 58.299, 242.071, -50.712, 0.718]

87.636