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: [219.345, 43.293, -71.722, 89.354, 78.234, 134.039, 137.045, 179.305, 1.526]

90.047