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: [95.472, 109.291, 245.955, 86.122, -90.639, 144.544, 31.063, 89.001, 40.671]

83.498